1 00:00:01,967 --> 00:00:03,166 NARRATOR: They're watching you. 2 00:00:03,166 --> 00:00:06,567 More than 6,000 satellites circle the Earth. 3 00:00:07,967 --> 00:00:09,767 Every day, they uncover new, 4 00:00:09,867 --> 00:00:13,400 mysterious phenomena that defy explanation. 5 00:00:16,166 --> 00:00:17,967 The nuke graveyard. 6 00:00:18,900 --> 00:00:21,867 They've all been dismantled and just left outside to rot. 7 00:00:23,567 --> 00:00:25,600 NARRATOR: The underwater ghost town. 8 00:00:26,600 --> 00:00:28,467 This place really is a mystery. 9 00:00:28,467 --> 00:00:30,000 I mean, a town literally emerged from a lake. 10 00:00:30,000 --> 00:00:31,467 I mean, a town literally emerged from a lake. 11 00:00:32,867 --> 00:00:35,567 NARRATOR: And China's mystery mega project. 12 00:00:36,567 --> 00:00:39,200 The scale of this is mind-boggling. 13 00:00:40,500 --> 00:00:44,200 NARRATOR: Baffling phenomena, mysteries from space. 14 00:00:44,266 --> 00:00:46,567 What on Earth are they? 15 00:00:46,567 --> 00:00:51,100 [theme music playing] 16 00:01:04,700 --> 00:01:08,166 January 2022. 17 00:01:08,266 --> 00:01:11,100 A satellite passing over Arizona scans 18 00:01:11,166 --> 00:01:14,266 100,000 square miles of barren desert 19 00:01:15,400 --> 00:01:17,567 and captures this far below. 20 00:01:19,367 --> 00:01:22,600 This is an amazing image -- you're seeing literally 21 00:01:22,667 --> 00:01:25,867 miles of aircraft lined up 22 00:01:25,867 --> 00:01:29,400 in precision on a flat desert floor. 23 00:01:29,467 --> 00:01:30,000 They almost look like toys lined up, ready to take off. 24 00:01:30,000 --> 00:01:33,166 They almost look like toys lined up, ready to take off. 25 00:01:35,800 --> 00:01:39,166 NARRATOR: Around 4,000 rusting military aircraft 26 00:01:39,166 --> 00:01:40,800 are arranged across an area 27 00:01:40,867 --> 00:01:44,767 equivalent to nearly 2,000 football fields. 28 00:01:44,767 --> 00:01:49,367 This place has got some of the coolest aircraft in history. 29 00:01:49,467 --> 00:01:54,367 We've got F-4 Phantoms, F-16s, F-15s, and we've 30 00:01:54,367 --> 00:01:57,100 even got test planes for the space programs. 31 00:01:57,166 --> 00:01:58,900 This place has it all. 32 00:02:01,567 --> 00:02:04,367 NARRATOR: Known locally as the Boneyard, 33 00:02:04,467 --> 00:02:08,266 this is the largest aircraft storage facility on Earth, 34 00:02:09,667 --> 00:02:12,767 yet among the lines of jets and helicopters 35 00:02:12,767 --> 00:02:14,867 is something that doesn't make sense. 36 00:02:17,467 --> 00:02:22,166 Looking closer, you see one very odd thing that sticks out. 37 00:02:23,767 --> 00:02:27,300 It's a very un-aircraft-shaped aircraft. 38 00:02:27,367 --> 00:02:30,000 In fact, it looks more like the hull of a boat. 39 00:02:31,767 --> 00:02:35,300 NARRATOR: Guy Walters studies the mystery hull in more detail. 40 00:02:37,066 --> 00:02:40,567 I think that these are the remains of an entirely 41 00:02:40,567 --> 00:02:42,567 different type of flying machine, 42 00:02:42,667 --> 00:02:45,100 and I think they're the remains of a blimp. 43 00:02:45,166 --> 00:02:47,166 You know, this is the hull 44 00:02:47,166 --> 00:02:49,867 where passengers and pilots are transported. 45 00:02:52,667 --> 00:02:55,100 NARRATOR: Air Force records confirm that the satellite has 46 00:02:55,166 --> 00:02:58,000 uncovered the remnants of a 400-foot-long 47 00:02:58,100 --> 00:03:00,000 ZPG-3W airship. 48 00:03:00,000 --> 00:03:00,767 ZPG-3W airship. 49 00:03:01,900 --> 00:03:04,967 This aircraft has a special place in history 50 00:03:04,967 --> 00:03:08,100 as one of the largest blimps ever built. 51 00:03:08,166 --> 00:03:10,266 It was involved in the Cold War, and it 52 00:03:10,367 --> 00:03:13,867 was indispensable to protecting America's interests 53 00:03:13,867 --> 00:03:15,166 during that war. 54 00:03:16,867 --> 00:03:20,900 The giant airship's story begins in the early 1950s. 55 00:03:22,266 --> 00:03:24,400 Fears are growing in Washington that 56 00:03:24,467 --> 00:03:27,800 the Soviet Union has developed a long-range nuclear bomber. 57 00:03:28,900 --> 00:03:30,000 When U.S. military attaches report what they witnessed at 58 00:03:30,000 --> 00:03:32,400 When U.S. military attaches report what they witnessed at 59 00:03:32,467 --> 00:03:33,867 a Soviet air show, 60 00:03:33,967 --> 00:03:36,100 those fears turn to panic. 61 00:03:36,166 --> 00:03:38,367 MORGAN: What they saw terrified them -- 62 00:03:38,467 --> 00:03:41,000 30 long-range bombers capable of 63 00:03:41,066 --> 00:03:44,467 carrying missiles over to the United States. 64 00:03:44,567 --> 00:03:47,567 WALTERS: That is getting the U.S. government really scared, 65 00:03:47,567 --> 00:03:49,667 because if you've got one air base 66 00:03:49,767 --> 00:03:51,000 like that in Russia, with as many 67 00:03:51,100 --> 00:03:54,066 as 30 of these bombers, then they're thinking there are gonna 68 00:03:54,066 --> 00:03:57,367 be hundreds of these bombers across the rest of the nation. 69 00:03:59,300 --> 00:04:00,000 NARRATOR: Intelligence analysts calculate that Moscow will soon 70 00:04:00,000 --> 00:04:02,300 NARRATOR: Intelligence analysts calculate that Moscow will soon 71 00:04:02,367 --> 00:04:05,567 possess around 600 long-range nuclear bombers, 72 00:04:07,266 --> 00:04:10,800 each capable of striking targets deep within the U.S. 73 00:04:13,100 --> 00:04:15,667 So there is a perception of something 74 00:04:15,667 --> 00:04:17,667 called the bomber gap, 75 00:04:17,767 --> 00:04:20,700 the fear that America is just not going to be able 76 00:04:20,767 --> 00:04:24,100 to withstand a long-range bombing campaign from 77 00:04:24,166 --> 00:04:26,100 the Soviet Union. 78 00:04:26,166 --> 00:04:28,266 WALTERS: You have American politicians now 79 00:04:28,367 --> 00:04:29,767 saying we don't have anything like 80 00:04:29,867 --> 00:04:30,000 the number of bombers that the Soviets have. 81 00:04:30,000 --> 00:04:31,300 the number of bombers that the Soviets have. 82 00:04:31,367 --> 00:04:33,767 These bombers they've got can wipe us out. 83 00:04:35,867 --> 00:04:36,867 NARRATOR: In response, 84 00:04:36,867 --> 00:04:40,767 by 1960, the U.S. military deploys a line of 85 00:04:40,867 --> 00:04:42,800 ZPG blimps in the Atlantic 86 00:04:42,867 --> 00:04:45,767 to scan for incoming Soviet bombers. 87 00:04:47,667 --> 00:04:51,567 CAVELL: These blimps can hold the air for days on end. 88 00:04:51,567 --> 00:04:54,100 They give us far better early warning 89 00:04:54,166 --> 00:04:57,000 system than any kind of aircraft possibly could. 90 00:04:59,500 --> 00:05:00,000 NARRATOR: During the airships' 91 00:05:00,000 --> 00:05:00,700 NARRATOR: During the airships' 92 00:05:00,767 --> 00:05:03,700 two-year-long deployment, the U.S. attempts to close 93 00:05:03,767 --> 00:05:07,900 the bomber gap by constructing hundreds of long-range B-52s. 94 00:05:09,467 --> 00:05:11,667 WALTERS: The B-52 is a living legend. 95 00:05:11,667 --> 00:05:13,867 It's sometimes called the Stratofortress, 96 00:05:13,867 --> 00:05:15,000 and that's kind of what it was. 97 00:05:15,100 --> 00:05:17,000 It was a flying fortress. 98 00:05:18,767 --> 00:05:21,166 NARRATOR: The massive rollout of the B-52 99 00:05:21,166 --> 00:05:24,100 costs an estimated $63 billion. 100 00:05:26,100 --> 00:05:28,600 But subsequent reconnaissance images reveal 101 00:05:28,667 --> 00:05:30,000 the entire program is rooted in one 102 00:05:30,000 --> 00:05:30,867 the entire program is rooted in one 103 00:05:30,867 --> 00:05:33,867 of the worst mistakes in intelligence history. 104 00:05:35,266 --> 00:05:38,500 When we saw those bombers in Russia 105 00:05:38,567 --> 00:05:41,367 years earlier, we were actually looking at 106 00:05:41,467 --> 00:05:44,400 the entire Soviet fleet of long-range bombers. 107 00:05:45,667 --> 00:05:50,467 So when the Americans go on to produce 750-odd B-52s, 108 00:05:50,467 --> 00:05:53,166 that's huge, huge overkill. 109 00:05:53,166 --> 00:05:56,867 It's a classic example of Cold War paranoia. 110 00:05:59,000 --> 00:06:00,000 NARRATOR: Despite its bizarre origins, the B-52 111 00:06:00,000 --> 00:06:02,467 NARRATOR: Despite its bizarre origins, the B-52 112 00:06:02,567 --> 00:06:04,100 goes on to become one of the most 113 00:06:04,166 --> 00:06:08,166 successful aircraft in history and is still in use today. 114 00:06:10,400 --> 00:06:14,000 This raises another mystery about the site seen from space. 115 00:06:16,467 --> 00:06:17,600 If you look at the Boneyard, 116 00:06:17,667 --> 00:06:20,367 it's chock-a-block with the remains of B-52s, 117 00:06:20,367 --> 00:06:23,266 and they've all been dismantled and just left outside to rot. 118 00:06:25,166 --> 00:06:27,567 There are a lot of these B-52s 119 00:06:27,667 --> 00:06:28,900 sitting there at the Boneyard. 120 00:06:29,000 --> 00:06:30,000 I mean, what is going on here? 121 00:06:30,000 --> 00:06:31,800 I mean, what is going on here? 122 00:06:31,867 --> 00:06:34,867 NARRATOR: Around 360 dismantled 123 00:06:34,867 --> 00:06:36,600 nuclear bombers litter the facility. 124 00:06:37,600 --> 00:06:41,066 Declassified documents reveal they are the legacy 125 00:06:41,066 --> 00:06:44,300 of a defining moment in U.S.-Soviet relations. 126 00:06:44,367 --> 00:06:48,767 The reason why we've got so many B-52s 127 00:06:48,767 --> 00:06:52,600 is because of a treaty called START 1. 128 00:06:52,667 --> 00:06:54,600 ORWOLL: START 1 was the first of 129 00:06:54,667 --> 00:06:56,867 the treaties that we did with the Soviet Union 130 00:06:56,867 --> 00:06:58,867 that was designed to limit the amount 131 00:06:58,867 --> 00:07:00,000 of nuclear weapons and nuclear weapon delivery vehicles. 132 00:07:00,000 --> 00:07:03,567 of nuclear weapons and nuclear weapon delivery vehicles. 133 00:07:04,867 --> 00:07:07,500 NARRATOR: As part of the 1991 treaty, 134 00:07:07,567 --> 00:07:12,367 the U.S. agrees to limit its fleet of B-52s to 71 bombers. 135 00:07:14,767 --> 00:07:16,367 Over the following years, 136 00:07:16,367 --> 00:07:19,100 the government tasks the Boneyard with decommissioning 137 00:07:19,166 --> 00:07:20,467 hundreds of the aircraft, 138 00:07:21,500 --> 00:07:24,367 creating the carnage visible in the image. 139 00:07:25,400 --> 00:07:28,166 JANULIS: By dismantling them in the Boneyard, the Russians could 140 00:07:28,266 --> 00:07:30,000 send their satellites over and see that 141 00:07:30,000 --> 00:07:30,300 send their satellites over and see that 142 00:07:30,367 --> 00:07:31,767 they were still dismantled, 143 00:07:31,767 --> 00:07:36,000 therefore reassuring them that we were reducing our ability to 144 00:07:36,066 --> 00:07:39,400 project lethal force to Russia. 145 00:07:42,667 --> 00:07:44,867 NARRATOR: Many of the B-52s' parts 146 00:07:44,867 --> 00:07:47,000 are recycled for use in other planes. 147 00:07:49,367 --> 00:07:52,767 Today, they and the thousands of other aircraft here 148 00:07:52,767 --> 00:07:54,667 are symbols of America's 149 00:07:54,667 --> 00:07:58,266 century-long dominance of the skies, visible from space. 150 00:07:59,467 --> 00:08:00,000 ORWOLL: This site may look like a graveyard of aircraft, 151 00:08:00,000 --> 00:08:02,266 ORWOLL: This site may look like a graveyard of aircraft, 152 00:08:02,266 --> 00:08:05,100 but it's actually preserving the legacy of these amazing 153 00:08:05,166 --> 00:08:06,467 airplanes and all 154 00:08:06,567 --> 00:08:08,266 the accomplishments that we've made. 155 00:08:15,200 --> 00:08:18,667 NARRATOR: Coming up, a mystery rises from the depths. 156 00:08:18,767 --> 00:08:22,000 It's really amazing to think how many chapters of 157 00:08:22,100 --> 00:08:25,600 U.S. history played out in this one small town. 158 00:08:26,767 --> 00:08:29,066 NARRATOR: And the Sponge City. 159 00:08:29,066 --> 00:08:30,000 It's an ingenious solution to a deadly problem. 160 00:08:30,000 --> 00:08:32,400 It's an ingenious solution to a deadly problem. 161 00:08:40,967 --> 00:08:44,200 NARRATOR: September 2021, 162 00:08:44,266 --> 00:08:47,266 drones flying high above the western U.S. state of 163 00:08:47,266 --> 00:08:48,767 Utah document 164 00:08:48,867 --> 00:08:51,667 falling water levels after one of the hottest summers 165 00:08:51,767 --> 00:08:52,767 in state history. 166 00:08:54,367 --> 00:08:58,967 The American West has been engulfed in 167 00:08:58,967 --> 00:09:03,200 a drought that has lasted for over 20 years. 168 00:09:03,266 --> 00:09:06,182 We're starting to use the term "megadrought." 169 00:09:06,182 --> 00:09:06,667 We're starting to use the term "megadrought." 170 00:09:09,066 --> 00:09:11,967 NARRATOR: As a camera passes over a receding body of water 171 00:09:11,967 --> 00:09:15,100 25 miles east of Salt Lake City, 172 00:09:15,166 --> 00:09:17,967 it captures a mystery emerging from the depths. 173 00:09:22,567 --> 00:09:24,166 KOUROUNIS: It's really remarkable. 174 00:09:24,266 --> 00:09:27,800 There are what appear to be some old buildings in ruins. 175 00:09:29,100 --> 00:09:31,500 There are these huge squares of rubble, which are 176 00:09:31,567 --> 00:09:33,967 the only remnants of what must have been people's homes 177 00:09:33,967 --> 00:09:35,133 and businesses. 178 00:09:37,266 --> 00:09:39,867 NARRATOR: The aerial images have uncovered the remains 179 00:09:39,967 --> 00:09:42,667 of a drowned settlement lost to history. 180 00:09:44,000 --> 00:09:45,967 MORGAN: This place really is a mystery. 181 00:09:45,967 --> 00:09:48,767 I mean, a town literally emerged from a lake. 182 00:09:48,767 --> 00:09:50,800 Why was it submerged? 183 00:09:50,867 --> 00:09:53,266 Where did the people who lived here go? 184 00:09:55,567 --> 00:09:57,166 NARRATOR: The first colonial settlements 185 00:09:57,266 --> 00:09:58,967 rise out of Utah's deserts as 186 00:09:58,967 --> 00:10:01,000 early as the 16th century, 187 00:10:01,066 --> 00:10:04,000 when Spanish Conquistadors plunder the state's mountains 188 00:10:04,100 --> 00:10:05,300 for gold. 189 00:10:06,567 --> 00:10:09,800 Historical records reveal these structures also belonged 190 00:10:09,867 --> 00:10:11,900 to settlers in search of riches, 191 00:10:12,000 --> 00:10:13,967 but of a spiritual kind. 192 00:10:15,200 --> 00:10:17,000 HUNT: It was a different group of people 193 00:10:17,100 --> 00:10:21,767 who are migrating west because of religious persecution. 194 00:10:21,867 --> 00:10:24,567 It was the Mormons who built this town. 195 00:10:26,967 --> 00:10:30,100 NARRATOR: Joseph Smith establishes the Mormon Church 196 00:10:30,166 --> 00:10:32,166 in Missouri in 1831, 197 00:10:32,166 --> 00:10:36,166 claiming to have received instructions from God, 198 00:10:36,166 --> 00:10:36,182 but his beliefs soon incur 199 00:10:36,182 --> 00:10:37,867 but his beliefs soon incur 200 00:10:37,967 --> 00:10:39,967 the wrath of other religious leaders. 201 00:10:39,967 --> 00:10:43,500 [indistinct shouting] 202 00:10:43,567 --> 00:10:46,467 HUNT: The Mormons' polygamy was a sin 203 00:10:46,567 --> 00:10:49,700 in the eyes of other conservative Christians 204 00:10:49,767 --> 00:10:52,567 in the Midwest, who drove them out. 205 00:10:53,867 --> 00:10:55,667 NARRATOR: After moving to Illinois, 206 00:10:55,767 --> 00:10:57,867 Smith is murdered by an angry mob. 207 00:10:57,867 --> 00:11:00,567 [gunshot blasts] 208 00:11:00,567 --> 00:11:02,367 To escape further bloodshed, 209 00:11:04,100 --> 00:11:06,182 in 1846, his 3,000 followers, inspired by the Biblical story 210 00:11:06,182 --> 00:11:09,800 in 1846, his 3,000 followers, inspired by the Biblical story 211 00:11:09,867 --> 00:11:12,467 of Jews who roamed the desert in search of 212 00:11:12,467 --> 00:11:14,600 their promised land move west. 213 00:11:16,667 --> 00:11:18,867 This would have been a journey through basically 214 00:11:18,867 --> 00:11:22,266 every hazard the Western Frontier can throw at you. 215 00:11:23,367 --> 00:11:27,367 You had wagons full of people 216 00:11:27,467 --> 00:11:30,567 who were dying, literally, along the way. 217 00:11:30,667 --> 00:11:36,182 This really was a very arduous journey out west. 218 00:11:36,182 --> 00:11:36,200 This really was a very arduous journey out west. 219 00:11:39,000 --> 00:11:41,266 NARRATOR: After a 1,000-mile trek, 220 00:11:41,266 --> 00:11:44,266 the Mormons reached the valley of the Great Salt Lake. 221 00:11:46,467 --> 00:11:50,467 There, they establish more than 350 communities 222 00:11:50,467 --> 00:11:53,200 and clear vast areas of land for agriculture. 223 00:11:54,300 --> 00:11:56,467 One of these new settlements that was established 224 00:11:56,567 --> 00:11:57,500 was Crandall, 225 00:11:57,500 --> 00:11:58,900 which is actually what we're looking at 226 00:11:59,000 --> 00:12:00,333 in this overhead image. 227 00:12:01,367 --> 00:12:05,300 HUNT: They said, "Let's build ourselves a paradise on Earth. 228 00:12:05,367 --> 00:12:06,182 "Nobody will persecute us, because there's nobody 229 00:12:06,182 --> 00:12:08,567 "Nobody will persecute us, because there's nobody 230 00:12:08,567 --> 00:12:10,367 else around." 231 00:12:10,467 --> 00:12:13,367 NARRATOR: But the Mormons' paradise is far from empty. 232 00:12:16,100 --> 00:12:18,000 For more than 1,000 years, 233 00:12:18,100 --> 00:12:20,667 the state has been the home and hunting grounds of 234 00:12:20,767 --> 00:12:22,000 the Ute people, 235 00:12:22,066 --> 00:12:24,967 a nomadic tribe who give Utah its name. 236 00:12:26,100 --> 00:12:29,667 The Ute were rightly upset that 237 00:12:29,667 --> 00:12:33,700 their way of life was changing 238 00:12:33,767 --> 00:12:36,182 and that they were losing their 239 00:12:36,182 --> 00:12:36,567 and that they were losing their 240 00:12:36,667 --> 00:12:40,066 tribe lands to these Mormon settlers. 241 00:12:41,967 --> 00:12:45,000 KERLEY: There was less supply of the wild animals that 242 00:12:45,100 --> 00:12:47,900 the Utes would hunt, and a number of Utes died 243 00:12:48,000 --> 00:12:49,100 from smallpox. 244 00:12:49,166 --> 00:12:51,166 They blamed the Mormons for bringing the disease, 245 00:12:51,166 --> 00:12:54,367 so now we have conflict between the Utes and the Mormons. 246 00:12:56,767 --> 00:12:59,867 NARRATOR: In 1865, the Ute chief, 247 00:12:59,867 --> 00:13:02,100 Antonga Black Hawk, forms an alliance 248 00:13:02,166 --> 00:13:05,900 with Navajo and Paiute tribes to wage war against 249 00:13:06,000 --> 00:13:06,182 the Mormons. 250 00:13:06,182 --> 00:13:07,266 the Mormons. 251 00:13:07,367 --> 00:13:13,200 The town of Crandall became a focal point for the war path, 252 00:13:13,266 --> 00:13:15,867 and the residents were terrified. 253 00:13:16,867 --> 00:13:18,567 JANULIS: They couldn't call on other settlements 254 00:13:18,567 --> 00:13:20,467 for aid quickly. 255 00:13:20,467 --> 00:13:23,667 So for their own self-defense and out of fear, 256 00:13:23,767 --> 00:13:26,367 they built a fort to protect themselves. 257 00:13:29,867 --> 00:13:33,000 After renaming their settlement Rock Fort, 258 00:13:33,100 --> 00:13:35,900 the Mormons negotiate a truce with Black Hawk. 259 00:13:37,100 --> 00:13:38,567 Over the following years, 260 00:13:38,567 --> 00:13:41,467 followers of the religion push deeper into the state, 261 00:13:41,567 --> 00:13:44,166 further shrinking Ute territories. 262 00:13:45,500 --> 00:13:47,700 This is a story that we see 263 00:13:47,767 --> 00:13:50,200 repeated throughout the United States. 264 00:13:50,266 --> 00:13:53,400 They had no plans of retreating. 265 00:13:53,467 --> 00:13:56,867 They were going to be in this space for 266 00:13:56,867 --> 00:14:00,200 a very long time, and they felt entitled to it. 267 00:14:01,467 --> 00:14:03,867 NARRATOR: However, the Mormons don't hold onto 268 00:14:03,967 --> 00:14:06,182 the land in the aerial images for long. 269 00:14:06,182 --> 00:14:06,300 the land in the aerial images for long. 270 00:14:10,300 --> 00:14:13,800 In 1952, the federal government purchases the valley, 271 00:14:13,867 --> 00:14:18,367 builds a dam, and turns it into a reservoir. 272 00:14:18,367 --> 00:14:20,367 They would have had to pack up their homes 273 00:14:20,367 --> 00:14:22,767 and businesses and sell them to the government. 274 00:14:22,767 --> 00:14:27,367 Any standing structures were demolished, literally bulldozed. 275 00:14:27,467 --> 00:14:31,300 After surviving 100 years of everything Utah could throw 276 00:14:31,367 --> 00:14:33,667 at it, this settlement is suddenly flooded. 277 00:14:37,867 --> 00:14:40,500 NARRATOR: The reservoir's waters may soon reclaim 278 00:14:40,567 --> 00:14:42,700 this relic of Utah's unique history. 279 00:14:43,667 --> 00:14:46,767 Until then, it endures as a reminder of some 280 00:14:46,767 --> 00:14:49,166 of the controversial events which helped form 281 00:14:49,166 --> 00:14:50,300 early America. 282 00:14:51,467 --> 00:14:54,200 It's really amazing to think of how many different 283 00:14:54,266 --> 00:14:55,867 and diverse chapters 284 00:14:55,967 --> 00:14:59,467 of U.S. history played out in this one small town. 285 00:15:07,700 --> 00:15:10,600 NARRATOR: Coming up, the killer river. 286 00:15:10,667 --> 00:15:12,967 The river has claimed so many lives, 287 00:15:12,967 --> 00:15:16,100 it's become known as China's sorrow. 288 00:15:16,166 --> 00:15:18,667 NARRATOR: And the land of the lost. 289 00:15:18,767 --> 00:15:21,266 This island becomes a dumping ground 290 00:15:21,266 --> 00:15:24,166 for society's unwanted people. 291 00:15:31,967 --> 00:15:36,667 NARRATOR: June 1, 2022 -- as a satellite 292 00:15:36,767 --> 00:15:39,166 studies the coastline of Southeast China, 293 00:15:39,266 --> 00:15:42,567 it captures a mystery on the outskirts of Shanghai. 294 00:15:47,266 --> 00:15:49,467 SZULGIT: This is a really interesting image. 295 00:15:49,567 --> 00:15:52,467 We're used to seeing city blocks that are square 296 00:15:52,467 --> 00:15:53,767 or rectangular, 297 00:15:53,767 --> 00:15:56,800 but this one's kind of a radiating circular pattern. 298 00:15:58,400 --> 00:16:00,567 What's even stranger is that much of 299 00:16:00,667 --> 00:16:02,467 it seems to be filled with water. 300 00:16:03,900 --> 00:16:06,800 This lake at the center is easily a mile 301 00:16:06,867 --> 00:16:10,100 and a half across -- it's a perfect circle, 302 00:16:10,166 --> 00:16:12,000 and it is enormous. 303 00:16:15,867 --> 00:16:18,867 NARRATOR: The strange circular mini city is dissected 304 00:16:18,967 --> 00:16:21,400 by a series of rivers or canals. 305 00:16:23,500 --> 00:16:26,467 KOUROUNIS: I can see waterways connecting from this lake 306 00:16:26,467 --> 00:16:27,893 back towards the city of Shanghai, 307 00:16:27,893 --> 00:16:29,467 back towards the city of Shanghai, 308 00:16:29,467 --> 00:16:33,600 but there are also waterways connecting to the ocean nearby. 309 00:16:33,667 --> 00:16:35,300 So I wonder if there's some link 310 00:16:35,367 --> 00:16:37,667 between that and what we're seeing here. 311 00:16:41,967 --> 00:16:44,266 NARRATOR: Analysts turn to local land records. 312 00:16:46,400 --> 00:16:50,567 They reveal that the 1.6-mile-wide superstructure 313 00:16:50,567 --> 00:16:53,200 is an attempt to prevent a disaster that threatens 314 00:16:53,266 --> 00:16:54,467 millions of lives. 315 00:16:55,467 --> 00:16:57,893 What we're looking at in the image is something that's 316 00:16:57,893 --> 00:16:58,000 What we're looking at in the image is something that's 317 00:16:58,100 --> 00:16:59,266 designed to deal with 318 00:16:59,266 --> 00:17:01,667 a problem that China has been plagued with for thousands 319 00:17:01,667 --> 00:17:03,967 of years, and that is flooding. 320 00:17:06,567 --> 00:17:09,767 NARRATOR: Catastrophic floods have plagued China since before 321 00:17:09,767 --> 00:17:14,200 the country's first ruling dynasty in the 21st century BCE. 322 00:17:16,000 --> 00:17:19,266 The worst floods in human history 323 00:17:19,367 --> 00:17:21,200 have taken place in China 324 00:17:22,800 --> 00:17:26,300 China often experiences heavy rains at the same time that 325 00:17:26,367 --> 00:17:27,893 the water, ice, and snowpack 326 00:17:27,893 --> 00:17:28,066 the water, ice, and snowpack 327 00:17:28,066 --> 00:17:31,467 in the mountains melts, and all of this water combines to make 328 00:17:31,567 --> 00:17:33,867 its rivers immensely destructive. 329 00:17:36,100 --> 00:17:39,266 NARRATOR: According to legend, the first attempts to tame 330 00:17:39,266 --> 00:17:44,266 China's raging rivers takes place around 2000 BCE. 331 00:17:44,367 --> 00:17:47,100 It is masterminded by Da Yu, 332 00:17:47,166 --> 00:17:48,767 known as Yu the Great, 333 00:17:48,767 --> 00:17:52,266 who goes on to become the first emperor of China. 334 00:17:53,367 --> 00:17:56,867 Yu the Great is this almost mythical figure who devised 335 00:17:56,967 --> 00:17:57,893 a system of canals, essentially 336 00:17:57,893 --> 00:17:58,700 a system of canals, essentially 337 00:17:58,767 --> 00:18:01,600 to divide up these mighty rivers and weaken their flow, 338 00:18:01,667 --> 00:18:03,667 making them less prone to flooding. 339 00:18:07,967 --> 00:18:10,166 NARRATOR: However, over the following centuries, 340 00:18:10,266 --> 00:18:13,000 thousands more floods devastate his country. 341 00:18:14,066 --> 00:18:17,266 One, on the Yellow River in 1887, 342 00:18:17,266 --> 00:18:19,400 kills almost a million people. 343 00:18:21,166 --> 00:18:23,667 The Yellow River has claimed so many lives, 344 00:18:23,767 --> 00:18:26,266 it's become known as China's Sorrow. 345 00:18:26,266 --> 00:18:27,893 It must be terrifying for the people that live there, 346 00:18:27,893 --> 00:18:28,900 It must be terrifying for the people that live there, 347 00:18:29,000 --> 00:18:31,767 knowing that, at almost any time, it could wreak terrible 348 00:18:31,867 --> 00:18:33,066 destruction on them. 349 00:18:34,767 --> 00:18:36,667 NARRATOR: Today, the threat of flooding 350 00:18:36,667 --> 00:18:39,066 in China is worse than ever. 351 00:18:39,066 --> 00:18:42,400 Experts warn that 98 percent of China's urban 352 00:18:42,467 --> 00:18:45,567 centers are in critical danger of being inundated. 353 00:18:47,967 --> 00:18:49,667 It's bad enough that climate change 354 00:18:49,767 --> 00:18:52,066 is causing much more rain every year, 355 00:18:52,066 --> 00:18:57,166 but add to that the fact that there is so much urban sprawl. 356 00:18:57,166 --> 00:18:57,893 Whenever you put down concrete, 357 00:18:57,893 --> 00:18:59,266 Whenever you put down concrete, 358 00:18:59,367 --> 00:19:02,367 it gives less places for this water to go. 359 00:19:02,367 --> 00:19:07,800 NARRATOR: Between 2011 and 2013, China laid more concrete than 360 00:19:07,867 --> 00:19:11,667 the United States did in the entire 20th century. 361 00:19:11,667 --> 00:19:13,900 This can be extremely dangerous for people who live 362 00:19:14,000 --> 00:19:16,500 in cities -- cities aren't good at absorbing water, 363 00:19:16,567 --> 00:19:18,367 and so they're prone to flash flooding. 364 00:19:20,066 --> 00:19:22,000 NARRATOR: Shanghai, where the circular 365 00:19:22,066 --> 00:19:25,266 mega project is located, is especially vulnerable. 366 00:19:25,367 --> 00:19:27,893 As well as the threat posed by the Yangtze River, 367 00:19:27,893 --> 00:19:28,367 As well as the threat posed by the Yangtze River, 368 00:19:28,367 --> 00:19:31,467 typhoons regularly batter the coast, 369 00:19:31,467 --> 00:19:35,100 and the number of times they make landfall is increasing. 370 00:19:35,166 --> 00:19:37,800 MORGAN: The population is suffering tremendously. 371 00:19:37,867 --> 00:19:40,867 Homes are washed away, loved ones are killed, 372 00:19:40,967 --> 00:19:43,567 and the government is not content to sit by 373 00:19:43,667 --> 00:19:45,800 and do nothing while that happens. 374 00:19:47,900 --> 00:19:49,467 NARRATOR: The site in the image is 375 00:19:49,567 --> 00:19:52,867 the Chinese authorities' solution to this crisis. 376 00:19:52,967 --> 00:19:55,767 It's called a sponge city. 377 00:19:57,200 --> 00:19:57,893 The essence of a sponge city isn't to stop the water, 378 00:19:57,893 --> 00:20:01,867 The essence of a sponge city isn't to stop the water, 379 00:20:01,967 --> 00:20:05,567 it's to hold onto it for a while so that you don't end up 380 00:20:05,667 --> 00:20:07,166 with catastrophic floods. 381 00:20:08,266 --> 00:20:11,567 SZULGIT: This manmade lake and these waterways are designed 382 00:20:11,667 --> 00:20:13,367 to help take some of the strain 383 00:20:13,467 --> 00:20:17,667 off the city's slow drainage by absorbing some of that overflow. 384 00:20:17,767 --> 00:20:20,667 It's an ingenious solution to a deadly problem. 385 00:20:22,300 --> 00:20:26,400 NARRATOR: Every element of the 30-square-mile, $120 million 386 00:20:26,467 --> 00:20:27,893 development is designed to combat the threat 387 00:20:27,893 --> 00:20:29,367 development is designed to combat the threat 388 00:20:29,467 --> 00:20:31,500 posed by flooding. 389 00:20:31,567 --> 00:20:35,100 These sponge cities incorporate various techniques, 390 00:20:35,166 --> 00:20:37,066 like underground water tanks, 391 00:20:37,066 --> 00:20:41,100 manmade wetlands, and rooftop gardens, to help control how 392 00:20:41,166 --> 00:20:43,467 fast the water gets absorbed into the ground. 393 00:20:44,700 --> 00:20:48,700 The wide streets have been built with permeable pavements. 394 00:20:48,767 --> 00:20:50,567 That allows the rainfall to 395 00:20:50,667 --> 00:20:54,166 soak into the ground rather than running off, 396 00:20:54,266 --> 00:20:57,893 allowing it to be controlled and not quite so destructive. 397 00:20:57,893 --> 00:20:58,467 allowing it to be controlled and not quite so destructive. 398 00:21:01,400 --> 00:21:04,700 NARRATOR: By 2030, China intends to install 399 00:21:04,767 --> 00:21:08,166 similar technology in 30 of its cities, 400 00:21:08,266 --> 00:21:12,166 hoping to end its millennia-long battle with floodwaters. 401 00:21:14,467 --> 00:21:17,900 This is a really great idea and a cool concept, 402 00:21:18,000 --> 00:21:21,900 but the question is, is this gonna be enough? 403 00:21:27,700 --> 00:21:27,893 NARRATOR: Coming up, island of the unknown. 404 00:21:27,893 --> 00:21:31,567 NARRATOR: Coming up, island of the unknown. 405 00:21:31,667 --> 00:21:34,567 This island has had a long history, 406 00:21:34,567 --> 00:21:38,900 and unfortunately, much of that history has been quite tragic. 407 00:21:39,000 --> 00:21:42,166 NARRATOR: And the mystery of the swamp mummies. 408 00:21:42,266 --> 00:21:44,467 These bodies seem to be associated with 409 00:21:44,567 --> 00:21:45,667 religious practices. 410 00:21:53,000 --> 00:21:57,000 NARRATOR: May 7th, 2021. 411 00:21:57,100 --> 00:22:00,367 A satellite scans the New York City borough of the Bronx 412 00:22:00,367 --> 00:22:01,800 and City Island, 413 00:22:01,867 --> 00:22:04,867 including some of the most sought after real estate on 414 00:22:04,867 --> 00:22:07,900 Earth, and captures something out of place. 415 00:22:10,066 --> 00:22:12,166 There's this very unusual island on 416 00:22:12,266 --> 00:22:14,266 the eastern seaboard of the United States. 417 00:22:15,867 --> 00:22:18,467 New York is a very densely populated, 418 00:22:18,567 --> 00:22:19,408 very expensive place to live, 419 00:22:19,408 --> 00:22:20,767 very expensive place to live, 420 00:22:21,767 --> 00:22:25,266 but you have this island with virtually nothing on it. 421 00:22:28,200 --> 00:22:29,500 NARRATOR: Elsewhere in New York, 422 00:22:29,567 --> 00:22:33,367 oceanfront properties can cost tens of millions of dollars. 423 00:22:34,667 --> 00:22:37,700 AUERBACH: You'd think that this would be hot property. 424 00:22:37,767 --> 00:22:41,400 Everything that you can build on, you build on. 425 00:22:41,467 --> 00:22:44,567 So why hasn't this island been built on? 426 00:22:44,667 --> 00:22:47,667 It almost looks like New Yorkers 427 00:22:47,767 --> 00:22:49,408 are intentionally avoiding this space, 428 00:22:49,408 --> 00:22:50,867 are intentionally avoiding this space, 429 00:22:50,967 --> 00:22:52,300 for whatever reason. 430 00:22:55,066 --> 00:22:57,767 NARRATOR: Analysts consult local historical records. 431 00:22:59,367 --> 00:23:01,600 They reveal something extraordinary. 432 00:23:03,166 --> 00:23:05,266 This island has had a long, 433 00:23:05,367 --> 00:23:08,467 varied history, and unfortunately, much of that 434 00:23:08,567 --> 00:23:10,567 history has been quite tragic. 435 00:23:12,066 --> 00:23:14,500 According to the documents, Hart Island, 436 00:23:14,567 --> 00:23:18,467 like much of New York, was once inhabited by Native Americans, 437 00:23:18,467 --> 00:23:19,408 the Siwanoy. 438 00:23:19,408 --> 00:23:19,667 the Siwanoy. 439 00:23:22,667 --> 00:23:25,166 In 1654, the tribe sells 440 00:23:25,266 --> 00:23:27,767 their ancestral lands to a British settler. 441 00:23:29,000 --> 00:23:32,100 After the period of colonization, 442 00:23:32,166 --> 00:23:35,200 the island passed through the hands of various wealthy 443 00:23:35,266 --> 00:23:36,467 private owners. 444 00:23:36,467 --> 00:23:40,800 KOUROUNIS: It seems they put it to some nefarious uses, 445 00:23:40,867 --> 00:23:43,567 the most famous being a venue for 446 00:23:43,567 --> 00:23:47,166 some pretty serious bare knuckle boxing matches. 447 00:23:49,767 --> 00:23:53,867 NARRATOR: Between 1800 and 1860, New York's population 448 00:23:53,867 --> 00:23:56,567 leaps from 60,000 to over a million. 449 00:23:58,367 --> 00:24:01,467 A quarter of the population are Irish immigrants, who bring 450 00:24:01,467 --> 00:24:03,667 their tradition of bare knuckle fights 451 00:24:03,667 --> 00:24:04,667 to the New World. 452 00:24:08,967 --> 00:24:11,600 But when authorities outlaw prize fighting 453 00:24:11,667 --> 00:24:13,200 in the mid-19th century, 454 00:24:13,266 --> 00:24:15,800 matches moved to the island in the image, 455 00:24:15,867 --> 00:24:19,408 along with many of the city's gangs and mobsters. 456 00:24:19,408 --> 00:24:19,467 along with many of the city's gangs and mobsters. 457 00:24:21,400 --> 00:24:24,100 These matches were so notorious that thousands 458 00:24:24,166 --> 00:24:27,100 of people would come over to witness them and bet on them. 459 00:24:28,367 --> 00:24:33,567 This is an underground spectator sport, and people 460 00:24:33,567 --> 00:24:35,567 would basically beat 461 00:24:35,667 --> 00:24:39,066 each other and pummel each other and participate in 462 00:24:39,066 --> 00:24:40,767 these lawless activities. 463 00:24:40,867 --> 00:24:45,166 One of the story goes that there was a big match between 464 00:24:45,266 --> 00:24:47,100 an Irishman and a Brit, 465 00:24:47,166 --> 00:24:49,408 and the crime rate went down because so many of the criminal 466 00:24:49,408 --> 00:24:50,500 and the crime rate went down because so many of the criminal 467 00:24:50,567 --> 00:24:52,900 types wanted to go watch the match. 468 00:24:53,000 --> 00:24:54,667 KOUROUNIS: These stories are colorful and all, 469 00:24:54,767 --> 00:24:57,066 but they don't really explain why the island is 470 00:24:57,066 --> 00:24:58,367 abandoned today. 471 00:25:00,667 --> 00:25:03,567 NARRATOR: Further aerial footage offers more clues. 472 00:25:05,000 --> 00:25:06,867 Some of these large, abandoned buildings on 473 00:25:06,867 --> 00:25:08,700 the island look like they once served 474 00:25:08,767 --> 00:25:10,367 an official purpose. 475 00:25:10,367 --> 00:25:13,667 They have this real institutional feel about them, 476 00:25:13,767 --> 00:25:15,400 like a location of a horror film 477 00:25:15,467 --> 00:25:17,567 where everything's just been left to rot. 478 00:25:19,867 --> 00:25:23,400 NARRATOR: By 1900, New York is the second largest 479 00:25:23,467 --> 00:25:26,166 and one of the wealthiest cities on Earth, 480 00:25:26,266 --> 00:25:29,400 the playground of the Rockefellers, Astors, 481 00:25:29,467 --> 00:25:31,100 and Vanderbilt families. 482 00:25:31,166 --> 00:25:34,100 During this so-called Gilded Age, 483 00:25:34,166 --> 00:25:37,467 at least half of the population also lives in poverty. 484 00:25:37,467 --> 00:25:40,767 Destitution is rife, and the island in 485 00:25:40,867 --> 00:25:42,767 the image takes on a new role. 486 00:25:42,767 --> 00:25:46,467 BROWN: The city would send people there that 487 00:25:46,567 --> 00:25:48,467 they didn't really want to deal with, 488 00:25:48,467 --> 00:25:49,408 and this island kind of becomes a dumping ground for 489 00:25:49,408 --> 00:25:51,767 and this island kind of becomes a dumping ground for 490 00:25:51,767 --> 00:25:56,266 society's unwanted groups of people. 491 00:25:56,367 --> 00:25:59,200 What we know is it was home to a workhouse, 492 00:25:59,266 --> 00:26:02,767 a women's psychiatric hospital, and even a prison for 493 00:26:02,867 --> 00:26:04,266 delinquent boys. 494 00:26:06,600 --> 00:26:08,467 NARRATOR: Yet it's the structures visible 495 00:26:08,467 --> 00:26:10,100 on the southern tip of the island, 496 00:26:10,166 --> 00:26:12,867 which explains its abandonment to this day. 497 00:26:14,567 --> 00:26:17,066 When we look, we see a series of 498 00:26:17,066 --> 00:26:19,408 white markers arranged in a quite orderly fashion. 499 00:26:19,408 --> 00:26:21,400 white markers arranged in a quite orderly fashion. 500 00:26:21,467 --> 00:26:25,300 Closer examination reveals that these are, in fact, graves. 501 00:26:27,767 --> 00:26:29,967 It seems this island does indeed have some 502 00:26:29,967 --> 00:26:31,066 permanent residents. 503 00:26:31,066 --> 00:26:35,000 It's home to hundreds of thousands of dead bodies. 504 00:26:35,066 --> 00:26:36,800 NARRATOR: For more than a century, 505 00:26:36,867 --> 00:26:39,800 the island is designated as a Potters Field, 506 00:26:39,867 --> 00:26:43,467 a burial site for unclaimed bodies. 507 00:26:43,467 --> 00:26:45,667 At the turn of the 21st century, 508 00:26:45,667 --> 00:26:49,408 up to 2,500 people a year are being interred here. 509 00:26:49,408 --> 00:26:49,700 up to 2,500 people a year are being interred here. 510 00:26:50,867 --> 00:26:54,567 The poor were buried here, criminals were also 511 00:26:54,567 --> 00:26:55,600 buried here. 512 00:26:55,667 --> 00:26:58,667 The mentally ill were buried here, and they 513 00:26:58,667 --> 00:27:02,400 were buried by prisoners as part of their punishment. 514 00:27:06,567 --> 00:27:09,266 NARRATOR: In more recent times, the island has been used 515 00:27:09,367 --> 00:27:10,600 to bury casualties of 516 00:27:10,667 --> 00:27:14,000 the COVID pandemic and some of the earliest victims 517 00:27:14,100 --> 00:27:15,600 of the HIV virus. 518 00:27:16,867 --> 00:27:19,408 At the time, there was a lot of hysteria over the disease. 519 00:27:19,408 --> 00:27:22,100 At the time, there was a lot of hysteria over the disease. 520 00:27:22,166 --> 00:27:25,000 So as a result, instead of giving -- being given a more 521 00:27:25,100 --> 00:27:27,767 dignified burial, the bodies were taken here. 522 00:27:29,567 --> 00:27:31,600 For over 140 years, 523 00:27:31,667 --> 00:27:33,867 this graveyard has been the burial site 524 00:27:33,867 --> 00:27:37,166 for New York City's marginalized and downtrodden. 525 00:27:38,467 --> 00:27:41,867 NARRATOR: Today, there are almost a million people buried 526 00:27:41,867 --> 00:27:43,800 on this seemingly empty island, 527 00:27:43,867 --> 00:27:47,967 meaning it is, in fact, more than 80 times more densely 528 00:27:47,967 --> 00:27:49,408 populated than Manhattan, 529 00:27:49,408 --> 00:27:50,467 populated than Manhattan, 530 00:27:50,467 --> 00:27:56,000 a symbol of our often troubled past visible from space. 531 00:27:56,066 --> 00:28:00,266 This island and its soil is a cross-section of 532 00:28:00,266 --> 00:28:04,367 the history of both New York and the history 533 00:28:04,467 --> 00:28:06,367 of its social tensions. 534 00:28:14,367 --> 00:28:18,166 NARRATOR: Coming up, gateway to the underworld. 535 00:28:18,166 --> 00:28:19,408 This was the nether land between the living and the dead. 536 00:28:19,408 --> 00:28:21,867 This was the nether land between the living and the dead. 537 00:28:23,200 --> 00:28:26,300 And the cloud catchers of Peru. 538 00:28:26,367 --> 00:28:30,667 The concept seems like science fiction, but actually worked. 539 00:28:39,100 --> 00:28:42,000 NARRATOR: April 11th, 2019. 540 00:28:42,066 --> 00:28:44,567 As an orbiting camera 541 00:28:44,667 --> 00:28:47,667 passes 400 miles above Wales, 542 00:28:47,767 --> 00:28:48,967 it captures an image of 543 00:28:48,967 --> 00:28:51,567 something that continues to puzzle experts. 544 00:28:53,100 --> 00:28:56,266 We're seeing a hillside, but then there's this strange 545 00:28:56,367 --> 00:28:57,900 scar on the side of it, 546 00:28:58,000 --> 00:29:00,667 this big zigzag, almost like a zipper. 547 00:29:02,667 --> 00:29:04,079 CEVERNEY: This is a really weird pattern. 548 00:29:04,079 --> 00:29:05,000 CEVERNEY: This is a really weird pattern. 549 00:29:05,100 --> 00:29:07,400 It's not something that we would find in nature. 550 00:29:07,467 --> 00:29:10,100 Nature doesn't create sawtooth patterns like this. 551 00:29:11,767 --> 00:29:15,000 NARRATOR: The mystery pattern stretches for around 800 feet 552 00:29:15,100 --> 00:29:17,867 down the flank of a barren, isolated mountainside. 553 00:29:19,867 --> 00:29:23,867 This is a really steep slope in the wilds of Wales, 554 00:29:23,867 --> 00:29:26,066 and whoever has gone in 555 00:29:26,066 --> 00:29:29,367 and done this has gone to a lot of trouble to do so. 556 00:29:31,667 --> 00:29:34,079 NARRATOR: To some analysts, the structure's shape 557 00:29:34,079 --> 00:29:34,100 NARRATOR: To some analysts, the structure's shape 558 00:29:34,166 --> 00:29:35,600 and location suggest 559 00:29:35,667 --> 00:29:39,000 it is a relic of this country's often violent past. 560 00:29:40,367 --> 00:29:44,600 It looks like some type of earthworks -- we're in Wales, 561 00:29:44,667 --> 00:29:46,667 and Wales was in a state of almost 562 00:29:46,667 --> 00:29:49,467 constant warfare with the neighboring English kingdom, 563 00:29:49,467 --> 00:29:52,100 so it wasn't uncommon for them to build 564 00:29:52,166 --> 00:29:53,467 these earthen work defenses, 565 00:29:53,567 --> 00:29:56,500 these dykes, to try to hold back invaders. 566 00:29:59,000 --> 00:30:00,900 NARRATOR: The country we now call Wales 567 00:30:01,000 --> 00:30:03,767 was once ruled by several warring kingdoms. 568 00:30:05,567 --> 00:30:08,100 Evidence of the battles they waged is visible 569 00:30:08,166 --> 00:30:10,700 in the form of defensive earthworks littering 570 00:30:10,767 --> 00:30:11,867 the landscape here. 571 00:30:12,867 --> 00:30:15,266 We tend to think of fortifications as being stone, 572 00:30:15,367 --> 00:30:17,967 but it's much easier to throw up dirt defenses. 573 00:30:17,967 --> 00:30:20,767 So we see these all around the region. 574 00:30:22,800 --> 00:30:24,967 NARRATOR: Geological records of the area 575 00:30:24,967 --> 00:30:26,767 surrounding the mystery structure 576 00:30:26,867 --> 00:30:29,200 reveal an abundance of peat bogs, 577 00:30:29,266 --> 00:30:33,467 a marshy landscape not suited to defensive structures. 578 00:30:34,467 --> 00:30:37,467 To some analysts, this instead suggests it may 579 00:30:37,567 --> 00:30:40,166 have once served a ceremonial purpose. 580 00:30:41,400 --> 00:30:46,266 It's possible that this is associated with rituals, 581 00:30:46,367 --> 00:30:48,867 because during prehistory, people would 582 00:30:48,867 --> 00:30:53,300 throw sacrificial victims into these bogs, 583 00:30:53,367 --> 00:30:55,967 and it seems that it was quite a common event. 584 00:30:58,200 --> 00:30:59,400 NARRATOR: Across Britain, 585 00:30:59,467 --> 00:31:02,867 archaeologists have pulled the remains of over 100 bodies 586 00:31:02,967 --> 00:31:04,079 from peaty marshlands like the one in the image. 587 00:31:04,079 --> 00:31:06,367 from peaty marshlands like the one in the image. 588 00:31:06,467 --> 00:31:08,900 They are known as bog bodies. 589 00:31:10,400 --> 00:31:14,000 These bog bodies are at least 2,000 years old. 590 00:31:14,100 --> 00:31:15,467 They seem to be associated with 591 00:31:15,467 --> 00:31:18,667 Celtic and possibly Druidic religious practices. 592 00:31:18,767 --> 00:31:21,667 NARRATOR: Peat bogs are formed of decaying 593 00:31:21,667 --> 00:31:24,767 layers of plant matter and moss. 594 00:31:24,867 --> 00:31:28,467 Their acidity and lack of oxygen makes them hostile to 595 00:31:28,467 --> 00:31:31,600 the bacteria and microbes that normally cause bodies 596 00:31:31,667 --> 00:31:32,767 to decompose. 597 00:31:36,467 --> 00:31:39,400 These peat bogs have extraordinary 598 00:31:39,467 --> 00:31:42,600 preservative properties -- I mean, to the point that 599 00:31:42,667 --> 00:31:46,200 they actually preserve bodies much the way 600 00:31:46,266 --> 00:31:48,900 an active mummification process would have. 601 00:31:51,166 --> 00:31:53,867 NARRATOR: Many bodies display signs of having endured 602 00:31:53,967 --> 00:31:57,266 violent deaths before being placed in the peat bogs. 603 00:32:00,467 --> 00:32:03,567 It's believed they were left as offerings to the gods 604 00:32:03,667 --> 00:32:04,079 in return for a good harvest or victories in battle. 605 00:32:04,079 --> 00:32:07,000 in return for a good harvest or victories in battle. 606 00:32:09,667 --> 00:32:14,266 In the old Celtic culture, bogs and marshes 607 00:32:14,367 --> 00:32:16,467 were the watery domain, 608 00:32:16,467 --> 00:32:19,900 the nether land between the living and the dead. 609 00:32:21,600 --> 00:32:24,867 It seems that they didn't actually hurl the body 610 00:32:24,867 --> 00:32:25,967 from the edge, 611 00:32:25,967 --> 00:32:27,800 but actually built little walkways. 612 00:32:27,867 --> 00:32:30,400 So it's possible that this is part 613 00:32:30,467 --> 00:32:33,500 of such a ritual route into the bog. 614 00:32:35,600 --> 00:32:38,200 NARRATOR: Karen Bellinger studies the image 615 00:32:38,266 --> 00:32:40,166 and develops a different theory. 616 00:32:41,266 --> 00:32:43,567 While the peat bogs in the area of 617 00:32:43,667 --> 00:32:46,000 this image could have been involved in 618 00:32:46,100 --> 00:32:47,900 ritualistic activities, 619 00:32:48,000 --> 00:32:50,200 I'm thinking that this image shows 620 00:32:50,266 --> 00:32:52,567 activity of a more recent nature. 621 00:32:54,200 --> 00:32:57,166 NARRATOR: To Bellinger, the weird zigzag is evidence 622 00:32:57,266 --> 00:32:59,767 of a practice known as peat harvesting. 623 00:33:00,967 --> 00:33:04,079 Peat has been an important natural resource for humanity 624 00:33:04,079 --> 00:33:04,300 Peat has been an important natural resource for humanity 625 00:33:04,367 --> 00:33:07,567 throughout antiquity, but in the 12th century in Europe, 626 00:33:07,667 --> 00:33:11,467 we start to see a real boom in its usage, but above all, as 627 00:33:11,467 --> 00:33:14,600 a fuel source to heat homes. 628 00:33:17,300 --> 00:33:19,667 NARRATOR: By the 13th century in Britain, 629 00:33:19,767 --> 00:33:22,667 wood-hungry industries like shipbuilding and a growing 630 00:33:22,767 --> 00:33:25,567 population mean that almost 80 percent 631 00:33:25,567 --> 00:33:27,400 of its woodlands have been felled. 632 00:33:30,300 --> 00:33:33,500 This forces many families to turn to the millions of acres 633 00:33:33,567 --> 00:33:34,079 of peatlands that once covered this island to heat their homes. 634 00:33:34,079 --> 00:33:37,100 of peatlands that once covered this island to heat their homes. 635 00:33:39,667 --> 00:33:42,200 HUNT: All across the landscape, 636 00:33:42,266 --> 00:33:47,100 people would come and take it out, square foot by square foot, 637 00:33:47,166 --> 00:33:51,367 and stack it and carry it away to be burned. 638 00:33:51,367 --> 00:33:53,867 Peat, because of its carbon capture properties, 639 00:33:53,867 --> 00:33:56,300 stores an immense amount of energy. 640 00:33:56,367 --> 00:33:58,900 It's so effective that it's actually 641 00:33:59,000 --> 00:34:01,767 outstripped wood as a source of heat. 642 00:34:03,166 --> 00:34:04,079 NARRATOR: Over the following centuries, 643 00:34:04,079 --> 00:34:05,000 NARRATOR: Over the following centuries, 644 00:34:05,066 --> 00:34:07,567 harvesters here in Britain and across the continent 645 00:34:07,667 --> 00:34:11,266 strip vast tracts of peatlands for fertilizer and fuel. 646 00:34:13,166 --> 00:34:15,900 In some European countries, this plunder accounts 647 00:34:16,000 --> 00:34:19,100 for around 10 percent of their entire surface area. 648 00:34:20,300 --> 00:34:24,000 Like chopping down trees, harvesting peat is 649 00:34:24,066 --> 00:34:26,000 heavy manual labor, I mean, 650 00:34:26,066 --> 00:34:30,367 you are literally carving slabs of turf out of the ground, 651 00:34:30,467 --> 00:34:32,467 and the process is known as peat cutting. 652 00:34:35,367 --> 00:34:37,700 NARRATOR: A single peat cutter can remove 653 00:34:37,767 --> 00:34:39,500 thousands of slabs per week. 654 00:34:42,000 --> 00:34:44,467 The zigzag shape in the image could have been 655 00:34:44,567 --> 00:34:46,567 a way for them to move their harvest 656 00:34:46,667 --> 00:34:48,567 across the steep terrain. 657 00:34:49,567 --> 00:34:51,567 RUBEN: They would extract it and pile it on sleds, 658 00:34:51,667 --> 00:34:52,767 but then they needed a way to 659 00:34:52,767 --> 00:34:54,767 get the sleds down the mountain safely. 660 00:34:54,767 --> 00:34:58,000 You can't have these things in straight channels, 661 00:34:58,066 --> 00:34:59,600 or the sledges would just careen 662 00:34:59,667 --> 00:35:01,266 down the mountain, so you have to cut them 663 00:35:01,266 --> 00:35:02,400 on the diagonal like this. 664 00:35:05,000 --> 00:35:07,900 NARRATOR: For now, this is just a theory. 665 00:35:08,000 --> 00:35:09,900 The exact purpose of the scar 666 00:35:10,000 --> 00:35:12,300 on the Welsh hillside remains a mystery, 667 00:35:12,367 --> 00:35:15,100 a gateway into this country's long, 668 00:35:15,166 --> 00:35:17,867 rich history, waiting to be deciphered. 669 00:35:22,500 --> 00:35:25,700 NARRATOR: Coming up, the Atacama cipher. 670 00:35:25,767 --> 00:35:28,800 You've got a checkerboard out in the middle of the desert, 671 00:35:28,867 --> 00:35:30,667 which really doesn't make any sense. 672 00:35:38,166 --> 00:35:40,967 NARRATOR: May 10th, 2022. 673 00:35:40,967 --> 00:35:44,500 A satellite scans the desolate mountains of 674 00:35:44,567 --> 00:35:48,767 western Peru and captures something that baffles analysts. 675 00:35:52,166 --> 00:35:53,166 SALAITA: All around, 676 00:35:53,266 --> 00:35:56,500 we're seeing just dry desert, it looks like, 677 00:35:56,567 --> 00:36:00,667 but right there is a big, black square. 678 00:36:03,166 --> 00:36:04,265 It's just bizarre. 679 00:36:04,265 --> 00:36:04,967 It's just bizarre. 680 00:36:05,967 --> 00:36:10,100 This gigantic square really stands out 681 00:36:10,166 --> 00:36:13,500 against the arid desert in the background. 682 00:36:13,567 --> 00:36:15,967 It really does look out of place. 683 00:36:19,500 --> 00:36:22,066 NARRATOR: Anthony Morgan studies the mystery structure 684 00:36:22,066 --> 00:36:24,066 in more detail. 685 00:36:24,066 --> 00:36:27,567 MORGAN: From a distance, there's clearly a grid pattern, 686 00:36:27,567 --> 00:36:30,100 but as you move closer, that pattern 687 00:36:30,166 --> 00:36:34,166 only becomes more complex, like woven cloth. 688 00:36:35,166 --> 00:36:38,000 NARRATOR: The structure reminds Morgan of ingenious pieces 689 00:36:38,066 --> 00:36:41,100 of engineering found throughout these arid deserts. 690 00:36:42,200 --> 00:36:44,000 Innovators in Peru have found ways 691 00:36:44,100 --> 00:36:47,200 to turn fog into drinking water, 692 00:36:48,266 --> 00:36:51,100 and they look similar to our image. 693 00:36:54,266 --> 00:36:56,900 NARRATOR: The structures are called fog catchers, 694 00:36:58,767 --> 00:37:01,500 and in this part of the world, they're a lifesaver. 695 00:37:04,000 --> 00:37:04,265 The Pacific coast of Peru is one 696 00:37:04,265 --> 00:37:05,800 The Pacific coast of Peru is one 697 00:37:05,867 --> 00:37:07,967 of the driest areas on the planet. 698 00:37:07,967 --> 00:37:11,900 It typically gets about a half inch of rain per year. 699 00:37:12,000 --> 00:37:14,367 CEVERNEY: There have been times where it hasn't rained 700 00:37:14,367 --> 00:37:18,867 for decades, so water is a very critical issue 701 00:37:18,967 --> 00:37:20,567 for the people who live here. 702 00:37:22,500 --> 00:37:25,567 NARRATOR: When cold air from the nearby Pacific Ocean 703 00:37:25,667 --> 00:37:27,500 hits Peru's warm coastal deserts, 704 00:37:27,567 --> 00:37:30,567 it forms towering blankets of fog, 705 00:37:30,567 --> 00:37:32,367 which sweep up into the mountains. 706 00:37:35,467 --> 00:37:39,000 The idea is to use very fine nets capable of collecting 707 00:37:39,100 --> 00:37:41,066 condensation from fog 708 00:37:41,066 --> 00:37:43,367 and draining it to a location where it can be used 709 00:37:43,467 --> 00:37:45,066 by locals. 710 00:37:45,066 --> 00:37:49,800 The concept of fog nets seems like science fiction, 711 00:37:49,867 --> 00:37:51,367 but it actually works. 712 00:37:54,166 --> 00:37:56,300 NARRATOR: Other analysts think the giant grid is 713 00:37:56,367 --> 00:37:58,767 dedicated to a different type of science. 714 00:38:02,166 --> 00:38:04,265 KOUROUNIS: Looking a little closer at the arrangement 715 00:38:04,265 --> 00:38:04,266 KOUROUNIS: Looking a little closer at the arrangement 716 00:38:04,367 --> 00:38:06,567 gives me a bit of a clue, 717 00:38:06,667 --> 00:38:10,900 in that perhaps this is a giant array of 718 00:38:11,000 --> 00:38:12,400 dipole antennas. 719 00:38:15,467 --> 00:38:18,300 ORWOLL: Dipole antennas are used from everything from 720 00:38:18,367 --> 00:38:20,667 transmitting television to listening 721 00:38:20,667 --> 00:38:22,700 to your local FM station. 722 00:38:22,767 --> 00:38:26,867 But when you put this many of them together in one location, 723 00:38:26,967 --> 00:38:28,367 now you're talking about something very 724 00:38:28,467 --> 00:38:31,100 significant going on at this site. 725 00:38:32,166 --> 00:38:34,265 NARRATOR: Local records confirm the array contains more than 726 00:38:34,265 --> 00:38:35,266 NARRATOR: Local records confirm the array contains more than 727 00:38:35,266 --> 00:38:38,367 18,000 dipole antennae, 728 00:38:38,467 --> 00:38:41,300 dedicated to studying the mysterious boundary between 729 00:38:41,367 --> 00:38:42,767 Earth and space. 730 00:38:44,400 --> 00:38:46,367 So what we have here is the Jicamarca 731 00:38:46,367 --> 00:38:47,667 Radio Observatory. 732 00:38:48,667 --> 00:38:50,767 It's one of the largest radars in 733 00:38:50,867 --> 00:38:54,400 the world and is used to study the ionosphere. 734 00:38:57,300 --> 00:39:01,467 NARRATOR: The ionosphere is a 190-mile-thick layer 735 00:39:01,467 --> 00:39:04,265 of charged particles formed by solar energy smashing into 736 00:39:04,265 --> 00:39:05,066 of charged particles formed by solar energy smashing into 737 00:39:05,066 --> 00:39:06,367 the Earth's atmosphere. 738 00:39:07,367 --> 00:39:09,266 For billions of years, it has 739 00:39:09,367 --> 00:39:12,467 shielded our planet from lethal solar radiation. 740 00:39:16,166 --> 00:39:18,400 But with the advent of spaceflight, 741 00:39:18,467 --> 00:39:21,467 scientists discover that this force field is a major 742 00:39:21,467 --> 00:39:25,467 obstacle to humankind's ambition to explore the cosmos. 743 00:39:27,567 --> 00:39:30,300 They find that the ionosphere makes communicating with 744 00:39:30,367 --> 00:39:34,265 manned spacecraft or satellites really difficult and unreliable. 745 00:39:34,265 --> 00:39:34,367 manned spacecraft or satellites really difficult and unreliable. 746 00:39:35,367 --> 00:39:38,500 When radio waves pass through this layer of the atmosphere, 747 00:39:38,567 --> 00:39:40,600 they are impacted by the ionosphere, 748 00:39:40,667 --> 00:39:42,066 and we need to know how, 749 00:39:42,066 --> 00:39:44,667 because this impacts our communications to space. 750 00:39:49,700 --> 00:39:53,200 NARRATOR: Construction of the observatory begins in 1960. 751 00:39:55,100 --> 00:39:58,266 By bouncing radio waves off the ionosphere, 752 00:39:58,367 --> 00:40:01,767 scientists measure its density and thickness, 753 00:40:01,767 --> 00:40:03,500 helping them better understand 754 00:40:03,567 --> 00:40:04,265 how to communicate with spacecraft. 755 00:40:04,265 --> 00:40:05,467 how to communicate with spacecraft. 756 00:40:08,300 --> 00:40:12,266 What they find is that the ionosphere is constantly in 757 00:40:12,367 --> 00:40:15,200 a state of flux -- when it's daytime on Earth, the ionosphere 758 00:40:15,266 --> 00:40:18,300 above grows -- when it's nighttime, it shrinks, 759 00:40:18,367 --> 00:40:22,000 but it's also affected by weather, both powerful storms 760 00:40:22,100 --> 00:40:24,900 on Earth or solar storms from the sun. 761 00:40:26,200 --> 00:40:29,367 NARRATOR: Observatories like Jicamarca have been critical to 762 00:40:29,367 --> 00:40:31,967 the thousands of satellites and spacecraft 763 00:40:31,967 --> 00:40:34,166 launched over the past six decades, 764 00:40:35,300 --> 00:40:38,867 but its success has presented it with a new challenge. 765 00:40:40,266 --> 00:40:43,567 This site is also studying what we call space junk. 766 00:40:44,900 --> 00:40:48,767 Space junk is garbage in orbit, 767 00:40:48,867 --> 00:40:52,867 basically, and it can be anything from used-up entire 768 00:40:52,867 --> 00:40:58,266 stages of rockets to things as small as paint chips from 769 00:40:58,266 --> 00:41:00,467 the space shuttle decades ago. 770 00:41:02,166 --> 00:41:04,265 NARRATOR: There are around 200,000 pieces of space junk, 771 00:41:04,265 --> 00:41:06,266 NARRATOR: There are around 200,000 pieces of space junk, 772 00:41:06,266 --> 00:41:09,567 from two-fifths of an inch to 4 inches in diameter, 773 00:41:09,667 --> 00:41:12,667 currently hurtling through orbits at speeds of up to 774 00:41:12,767 --> 00:41:15,900 18,000 miles per hour. 775 00:41:16,000 --> 00:41:18,700 One problem that we're worried about is if there is 776 00:41:18,767 --> 00:41:23,500 a cascading effect, if one piece of space junk hits a satellite, 777 00:41:23,567 --> 00:41:27,200 destroys that satellite, and then the pieces of space junk 778 00:41:27,266 --> 00:41:29,166 from that impact move on to 779 00:41:29,266 --> 00:41:32,100 destroy more satellites and more satellites. 780 00:41:34,166 --> 00:41:34,265 NARRATOR: By forensically tracking this debris, 781 00:41:34,265 --> 00:41:36,967 NARRATOR: By forensically tracking this debris, 782 00:41:38,600 --> 00:41:42,100 the site in the image protects us from the very craft it 783 00:41:42,166 --> 00:41:44,367 helped put into space. 784 00:41:44,367 --> 00:41:48,367 JRO helps monitor the movement of these pieces of space junk, 785 00:41:48,367 --> 00:41:51,567 the small ones, the large ones, and we can then move that 786 00:41:51,667 --> 00:41:53,166 spacecraft early enough so that 787 00:41:53,166 --> 00:41:56,400 we don't have a catastrophic impact with Earth.