1 00:00:01,502 --> 00:00:03,202 NARRATOR: They're watching you. 2 00:00:03,337 --> 00:00:06,238 More than 6,000 satellites circle the Earth. 3 00:00:07,408 --> 00:00:09,241 Every day, they uncover new, 4 00:00:09,343 --> 00:00:12,911 mysterious phenomena that defy explanation. 5 00:00:15,316 --> 00:00:17,116 From orbit, 6 00:00:17,218 --> 00:00:19,318 the lost doomsday lair. 7 00:00:21,555 --> 00:00:23,789 This place played a crucial role 8 00:00:23,791 --> 00:00:26,058 in the fate of millions of lives. 9 00:00:26,160 --> 00:00:30,229 NARRATOR: The hunt for the birthplace of humanity. 10 00:00:30,331 --> 00:00:32,631 This is an astonishing discovery. 11 00:00:33,601 --> 00:00:36,835 NARRATOR: And inside the New Jersey apocalypse zone. 12 00:00:36,837 --> 00:00:40,439 What you've got is a scene that's beyond horrifying. 13 00:00:41,942 --> 00:00:44,543 NARRATOR: Baffling phenomena, mysteries from space. 14 00:00:44,612 --> 00:00:46,712 What on Earth are they? 15 00:00:46,847 --> 00:00:49,448 [theme music playing] 16 00:01:04,331 --> 00:01:07,132 July 2020. 17 00:01:07,234 --> 00:01:11,036 A satellite flying over Southern Europe 18 00:01:11,138 --> 00:01:14,807 scans the Greek island of Kefalonia 19 00:01:14,809 --> 00:01:17,643 and spots strange structures on a mountain peak. 20 00:01:19,713 --> 00:01:22,047 RODRIGUEZ McROBBIE: We're looking at some kind of 21 00:01:22,116 --> 00:01:25,617 compound in a very remote location. 22 00:01:25,686 --> 00:01:27,519 And looking a bit closer, 23 00:01:27,521 --> 00:01:32,157 you can see what appear to be fences all around the edges. 24 00:01:34,361 --> 00:01:38,063 Clearly, whatever's there is either very valuable, or someone 25 00:01:38,099 --> 00:01:42,201 wants to make sure that it doesn't have uninvited guests. 26 00:01:42,303 --> 00:01:44,303 NARRATOR: What's more, 27 00:01:44,305 --> 00:01:47,339 the mystery facility is not alone. 28 00:01:47,441 --> 00:01:49,608 WALTERS: This site is basically weird enough, 29 00:01:49,710 --> 00:01:54,246 but there are loads of nearly identical structures dotted all 30 00:01:54,348 --> 00:01:56,949 over mountaintops all across Europe. 31 00:01:58,619 --> 00:02:02,321 NARRATOR: More than 80 sites extend across 8,000 miles of 32 00:02:02,389 --> 00:02:04,456 the continent. 33 00:02:04,525 --> 00:02:06,825 MORAN: This is super perplexing. 34 00:02:06,927 --> 00:02:09,728 They seem to be aligned in a kind of giant 35 00:02:09,730 --> 00:02:13,632 semicircle stretching from northern Norway, 36 00:02:13,734 --> 00:02:16,235 down through mainland Europe and all the way into Turkey. 37 00:02:17,505 --> 00:02:20,005 It must have involved a massive amount of 38 00:02:20,007 --> 00:02:24,510 international cooperation and also a vast amount of money. 39 00:02:24,612 --> 00:02:27,045 But what their purpose is, is less clear. 40 00:02:32,520 --> 00:02:35,754 NARRATOR: On the hunt for answers, Dutch urban explorers 41 00:02:35,856 --> 00:02:37,956 are heading for the mountaintop compound 42 00:02:38,058 --> 00:02:39,458 seen from space. 43 00:02:54,108 --> 00:02:56,008 [high-pitched beeping noise] 44 00:03:00,514 --> 00:03:01,947 Yes. 45 00:03:02,049 --> 00:03:04,616 [high-pitched beeping noise] 46 00:03:08,822 --> 00:03:11,356 NARRATOR: The site's owners are long gone, 47 00:03:11,425 --> 00:03:14,259 but giant clues to its purpose remain. 48 00:03:24,905 --> 00:03:27,039 NARRATOR: The mountaintop dishes are each 49 00:03:27,140 --> 00:03:28,941 over 60 feet in diameter. 50 00:03:40,588 --> 00:03:42,821 MUNOZ: What this appears to be is 51 00:03:42,923 --> 00:03:45,624 some kind of communication station. 52 00:03:45,726 --> 00:03:49,728 But look at the scope and scale of this. 53 00:03:49,830 --> 00:03:51,630 It's unlike anything that I've ever seen. 54 00:03:53,601 --> 00:03:55,300 If you look at the age of this facility, 55 00:03:55,302 --> 00:03:58,003 to me, it looks decades old, and that could 56 00:03:58,005 --> 00:04:01,006 put it right at the heart of the Cold War. 57 00:04:02,309 --> 00:04:05,944 NARRATOR: Experts turn to declassified records 58 00:04:06,046 --> 00:04:07,946 to decipher the site's purpose. 59 00:04:09,049 --> 00:04:12,050 AUERBACH: Further investigation reveals that these are 60 00:04:12,119 --> 00:04:15,420 all part of a very secretive communication network 61 00:04:15,522 --> 00:04:17,956 known as the Allied Command 62 00:04:18,058 --> 00:04:21,226 Europe Highband, or ACE High. 63 00:04:22,763 --> 00:04:24,229 NARRATOR: According to the records, 64 00:04:24,331 --> 00:04:25,564 the network's origins lie 65 00:04:25,599 --> 00:04:27,733 at the very start of the Cold War, 66 00:04:30,304 --> 00:04:33,939 when increasing Soviet aggression threatens to spark 67 00:04:34,008 --> 00:04:36,541 conflict between East and West. 68 00:04:36,643 --> 00:04:39,144 In 1948, 69 00:04:39,213 --> 00:04:43,815 we see Stalin severely testing Western resolve by 70 00:04:43,817 --> 00:04:46,251 blockading Berlin, 71 00:04:46,320 --> 00:04:47,653 and the U.S. knew that she just 72 00:04:47,754 --> 00:04:51,623 had to act, and NATO was the result. 73 00:04:55,029 --> 00:04:56,962 NARRATOR: NATO -- short for 74 00:04:57,097 --> 00:04:59,431 the North Atlantic Treaty Organization -- 75 00:04:59,433 --> 00:05:02,501 is a defensive alliance between the U.S., Canada, 76 00:05:02,603 --> 00:05:04,803 and 12 European nations. 77 00:05:04,905 --> 00:05:07,439 Its objective is to use collective military 78 00:05:07,508 --> 00:05:10,509 might as a deterrent against possible conflict. 79 00:05:13,213 --> 00:05:16,114 One of NATO's great strengths is the large 80 00:05:16,216 --> 00:05:19,151 number of countries that are included in it. 81 00:05:19,252 --> 00:05:21,620 But this is also, in some ways, a weakness, because it 82 00:05:21,722 --> 00:05:24,656 makes communication amongst these different countries 83 00:05:24,725 --> 00:05:27,259 a much more complex process. 84 00:05:27,327 --> 00:05:29,328 What makes things worse is that some of 85 00:05:29,330 --> 00:05:32,130 the countries' individual communication systems 86 00:05:32,132 --> 00:05:34,099 were open to interception. 87 00:05:34,201 --> 00:05:38,870 Basically, it left NATO horribly exposed. 88 00:05:38,872 --> 00:05:41,106 NARRATOR: Sensing a weakness, 89 00:05:41,108 --> 00:05:44,609 the Soviet Union pours tens of millions of dollars into 90 00:05:44,745 --> 00:05:48,146 a campaign of electronic warfare against NATO. 91 00:05:48,215 --> 00:05:52,250 [electronic noises] 92 00:05:52,352 --> 00:05:55,120 200 radio-jamming stations target and cut 93 00:05:55,122 --> 00:05:58,123 off communication lines between the Allied states. 94 00:06:00,027 --> 00:06:03,462 Stalin threw the might of the Soviet Union 95 00:06:03,563 --> 00:06:06,431 into campaigns to disrupt the Western alliance, 96 00:06:06,500 --> 00:06:09,134 because he knew a united NATO 97 00:06:09,203 --> 00:06:12,504 was much stronger than countries acting alone. 98 00:06:14,508 --> 00:06:16,208 RODRIGUEZ McROBBIE: NATO know that they need 99 00:06:16,310 --> 00:06:18,243 to seriously up their game. 100 00:06:18,345 --> 00:06:21,012 In times of war, cold or hot, 101 00:06:21,014 --> 00:06:23,715 it is essential that military leaders are able 102 00:06:23,717 --> 00:06:25,150 to communicate. 103 00:06:25,219 --> 00:06:27,719 [indistinct talking] 104 00:06:27,854 --> 00:06:31,323 NARRATOR: In 1956, NATO responds by commissioning 105 00:06:31,458 --> 00:06:34,059 the ACE High system, 106 00:06:34,128 --> 00:06:36,061 a unified network that serves as 107 00:06:36,130 --> 00:06:38,864 a secure line between Allied leaders. 108 00:06:40,300 --> 00:06:43,034 The whole project was conducted under the tightest 109 00:06:43,103 --> 00:06:45,404 possible security to make sure that 110 00:06:45,506 --> 00:06:47,739 no information about this leaked back to 111 00:06:47,841 --> 00:06:49,908 the Kremlin. 112 00:06:49,910 --> 00:06:51,710 There's very little information about 113 00:06:51,712 --> 00:06:54,212 the nuts and bolts of the ACE High. 114 00:06:54,314 --> 00:06:58,116 The details are still shrouded in mystery. 115 00:07:01,955 --> 00:07:03,722 NARRATOR: To learn more, 116 00:07:03,724 --> 00:07:06,558 the urban explorers hike to another site rumored 117 00:07:06,660 --> 00:07:08,927 to have played a role in ACE High. 118 00:07:14,435 --> 00:07:17,502 NARRATOR: But it appears the rumors were wrong. 119 00:07:52,306 --> 00:07:55,407 [grunting] 120 00:07:55,409 --> 00:07:58,310 NARRATOR: The mile-long tunnel guides the explorers into 121 00:07:58,312 --> 00:08:02,113 a labyrinthine compound hidden deep inside the mountain. 122 00:08:07,554 --> 00:08:11,256 Whenever you walk into a sealed Cold War facility, 123 00:08:11,291 --> 00:08:15,160 you've really got no idea what you're going to encounter. 124 00:08:15,228 --> 00:08:17,429 Who knows what's been locked away in here 125 00:08:17,431 --> 00:08:18,730 for all these years. 126 00:08:35,616 --> 00:08:38,416 NARRATOR: Encased in millions of tons of rock is 127 00:08:38,519 --> 00:08:41,953 a network of rooms split over multiple floors. 128 00:09:10,751 --> 00:09:12,717 Look at this place! It's absolutely incredible. 129 00:09:12,719 --> 00:09:15,153 There are military maps, there are control desks. 130 00:09:15,222 --> 00:09:17,622 It's like something out of Dr. Strangelove. 131 00:09:18,759 --> 00:09:21,159 NARRATOR: The team has discovered evidence of 132 00:09:21,228 --> 00:09:24,029 the ACE High network's most clandestine mission. 133 00:09:25,265 --> 00:09:28,934 At one point, this place played a crucial 134 00:09:29,002 --> 00:09:32,304 role in the fate of countless millions of lives. 135 00:09:38,412 --> 00:09:42,314 NARRATOR: Coming up, on the front line of Armageddon. 136 00:09:42,449 --> 00:09:46,418 Seconds can mean the difference between life and death. 137 00:09:48,055 --> 00:09:51,056 NARRATOR: And one of the weirdest trips in history. 138 00:09:51,124 --> 00:09:54,526 They came up with a very 1960s answer -- 139 00:09:54,628 --> 00:09:56,461 they gave the elephants LSD. 140 00:10:07,608 --> 00:10:11,109 NARRATOR: Lured by mountaintop compounds captured from space, 141 00:10:15,215 --> 00:10:17,616 urban explorers have discovered a hidden command 142 00:10:17,718 --> 00:10:20,552 center of NATO's ACE High communications network. 143 00:10:28,629 --> 00:10:31,329 NARRATOR: This facility played a vital role in some 144 00:10:31,331 --> 00:10:33,765 of the darkest days of the 20th century. 145 00:10:35,202 --> 00:10:36,635 This place kind of blows me away. 146 00:10:36,736 --> 00:10:39,437 It's a kind of a lost command center for one 147 00:10:39,539 --> 00:10:43,942 of the most secretive NATO operations of the Cold War. 148 00:10:48,682 --> 00:10:50,548 NARRATOR: According to Cold War documents, 149 00:10:50,650 --> 00:10:53,184 NATO begins constructing the command center, 150 00:10:53,186 --> 00:10:58,523 code-named Proto, in the late 1950s. 151 00:10:58,525 --> 00:11:01,960 Working in conjunction with 82 giant radar stations 152 00:11:02,029 --> 00:11:04,462 built on mountaintops across Europe, 153 00:11:04,531 --> 00:11:05,830 its mission is to monitor 154 00:11:05,832 --> 00:11:08,900 the Iron Curtain for incoming nuclear missiles. 155 00:11:11,705 --> 00:11:13,104 At the start of the Cold War, 156 00:11:13,106 --> 00:11:15,540 there are no anti-ballistic missile systems. 157 00:11:15,609 --> 00:11:17,842 So if the Soviets do laun, 158 00:11:17,944 --> 00:11:20,945 the only thing that we can do is sound the alarm for every 159 00:11:21,081 --> 00:11:24,416 NATO ally to get ready for impact. 160 00:11:28,321 --> 00:11:30,055 NARRATOR: In a worst-case scenario, 161 00:11:30,123 --> 00:11:31,723 military leaders predict over 162 00:11:31,725 --> 00:11:35,760 2,000 Soviet nukes will launch in a colossal first strike. 163 00:11:37,431 --> 00:11:40,832 Once detected and confirmed, the alarm fires through 164 00:11:40,934 --> 00:11:43,201 the ACE High network at the speed of light. 165 00:11:44,404 --> 00:11:47,639 The technology being used at these radar locations 166 00:11:47,741 --> 00:11:48,907 is twofold. 167 00:11:48,909 --> 00:11:52,444 We have a standard radio wave receiver. 168 00:11:52,545 --> 00:11:55,013 They're also using a newer technology, 169 00:11:55,115 --> 00:11:56,815 which was troposcatter. 170 00:12:00,020 --> 00:12:03,054 NARRATOR: Troposcatter dishes bounce microwaves off layers in 171 00:12:03,123 --> 00:12:06,691 the atmosphere and on to the next station in the network. 172 00:12:06,693 --> 00:12:08,560 Upon receiving the signal, 173 00:12:08,628 --> 00:12:11,629 that station automatically forwards on the alarm. 174 00:12:13,934 --> 00:12:17,702 It basically acts like a giant trip wire 175 00:12:17,704 --> 00:12:20,305 to alert of the incoming Soviet attack. 176 00:12:21,808 --> 00:12:24,109 RODRIGUEZ McROBBIE: This is why the ACE High system 177 00:12:24,211 --> 00:12:26,444 is crucial for the Allies. 178 00:12:26,513 --> 00:12:29,247 It is able to send out an alert across Europe in 179 00:12:29,316 --> 00:12:31,116 a heartbeat at a time 180 00:12:31,184 --> 00:12:33,518 when seconds can mean the difference 181 00:12:33,620 --> 00:12:37,155 between life and death. 182 00:12:37,257 --> 00:12:40,458 NARRATOR: NATO commanders hope this alert will provide enough 183 00:12:40,527 --> 00:12:44,229 time to evacuate key personnel from the Soviets' targets. 184 00:12:45,732 --> 00:12:47,732 WALTERS: The reality is that there's no way 185 00:12:47,834 --> 00:12:48,799 you can save everybody. 186 00:12:48,802 --> 00:12:50,802 Once you've taken away the time needed 187 00:12:50,904 --> 00:12:53,438 to detect the missile and then confirm it, 188 00:12:53,540 --> 00:12:55,840 the British government reckoned they had about enough 189 00:12:55,975 --> 00:12:59,911 time it takes to make a coffee before impact. 190 00:13:01,515 --> 00:13:03,815 NARRATOR: Intelligence analysts calculate the first 191 00:13:03,884 --> 00:13:05,817 bombs would strike European cities 192 00:13:05,819 --> 00:13:08,219 four minutes after the alarm sounds. 193 00:13:10,557 --> 00:13:13,925 [explosion blasts] 194 00:13:13,927 --> 00:13:16,795 ANNOUNCER: The Austin area may be hit by missiles. 195 00:13:16,863 --> 00:13:19,464 There will not be time to evacuate. 196 00:13:19,566 --> 00:13:22,834 NARRATOR: Minutes later, warheads descend on the U.S., 197 00:13:22,936 --> 00:13:25,703 [explosion blasts] 198 00:13:28,241 --> 00:13:31,409 killing a predicted 160 million civilians. 199 00:13:31,511 --> 00:13:36,114 Top-ranking NATO officials knew that the civilian 200 00:13:36,216 --> 00:13:40,451 death count was going to be enormous. 201 00:13:40,553 --> 00:13:43,321 Their plan was to save themselves 202 00:13:43,423 --> 00:13:45,957 in order to serve their country. 203 00:13:46,026 --> 00:13:48,626 NARRATOR: As hellfire rains down, 204 00:13:48,628 --> 00:13:51,129 officials based in the command center would use 205 00:13:51,131 --> 00:13:53,431 the ACE High network to help coordinate 206 00:13:53,500 --> 00:13:55,934 an unprecedented counterstrike. 207 00:13:57,304 --> 00:14:01,239 NATO forces had amassed a huge nuclear arsenal 208 00:14:01,341 --> 00:14:04,142 to create a stalemate that would never be broken. 209 00:14:04,211 --> 00:14:07,946 But what they knew is that if the Soviets made the first move 210 00:14:08,047 --> 00:14:09,948 by firing their missiles, 211 00:14:10,049 --> 00:14:13,017 they would need to retaliate in full. 212 00:14:16,022 --> 00:14:17,956 NARRATOR: During such a retaliation, 213 00:14:18,024 --> 00:14:21,526 NATO could unleash over 10,000 thermonuclear bombs 214 00:14:21,628 --> 00:14:23,628 and missiles. 215 00:14:23,630 --> 00:14:27,298 Some are over one-and-a-half-thousand times 216 00:14:27,300 --> 00:14:31,135 more powerful than the nuke that destroyed Hiroshima. 217 00:14:31,237 --> 00:14:36,207 The result is intended to completely annihilate 218 00:14:36,209 --> 00:14:38,743 the Soviet Union, striking at every major city, 219 00:14:38,845 --> 00:14:42,313 every identified military complex, in order to wipe 220 00:14:42,415 --> 00:14:45,116 the Soviet Union off the face of the Earth. 221 00:14:45,218 --> 00:14:48,820 [explosion blasts] 222 00:14:55,829 --> 00:14:58,363 NARRATOR: The urban explorers see evidence that 223 00:14:58,464 --> 00:15:00,398 the ACE High network could maintain 224 00:15:00,400 --> 00:15:02,400 NATO communications for several weeks 225 00:15:02,502 --> 00:15:03,935 following a nuclear onslaught, 226 00:15:05,138 --> 00:15:08,606 long enough for fallout to drop to survivable levels. 227 00:15:20,353 --> 00:15:23,955 NARRATOR: The ACE High network secretly maintains vital lines 228 00:15:24,057 --> 00:15:28,326 of communication until 1996, 5 years after 229 00:15:28,428 --> 00:15:31,029 the Soviet Union disintegrates. 230 00:15:31,031 --> 00:15:33,765 Today, these structures are haunting evidence 231 00:15:33,833 --> 00:15:36,100 of the reality of nuclear conflict. 232 00:15:38,805 --> 00:15:40,805 MUNOZ: Even though they're not operational anymore, 233 00:15:40,807 --> 00:15:43,241 these structures sort of have a new mission. 234 00:15:43,343 --> 00:15:45,343 They kind of serve as a reminder for 235 00:15:45,445 --> 00:15:49,247 how close we actually came to World War III. 236 00:15:58,024 --> 00:16:01,726 NARRATOR: Coming up, a truly monster roadblock. 237 00:16:01,828 --> 00:16:04,128 This is the kind of situation that could get ugly. 238 00:16:05,532 --> 00:16:08,599 NARRATOR: And the 4,000-year-old desert treasure hunt. 239 00:16:08,601 --> 00:16:10,601 This area was once the epicenter 240 00:16:10,603 --> 00:16:12,103 of the ancient world. 241 00:16:21,948 --> 00:16:25,016 NARRATOR: Xishuangbanna Nature Reserve, Southwest China. 242 00:16:26,453 --> 00:16:28,953 This vast protected rainforest is home 243 00:16:29,055 --> 00:16:31,622 to hundreds of endangered Asian elephants. 244 00:16:33,259 --> 00:16:37,929 But in March 2020, eyes in the sky spot a baffling sight. 245 00:16:41,301 --> 00:16:43,601 What's happening with this particular herd 246 00:16:43,603 --> 00:16:45,136 is really weird. 247 00:16:45,238 --> 00:16:48,106 KAYS: They left the park, they're walking into areas 248 00:16:48,108 --> 00:16:49,941 where people are living, 249 00:16:50,043 --> 00:16:53,945 people are farming, and they just keep going. 250 00:16:54,047 --> 00:16:57,248 They just keep walking and walking and walking. 251 00:16:59,919 --> 00:17:02,120 NARRATOR: Drones track the 16 elephants 252 00:17:02,122 --> 00:17:04,322 as they march on for weeks, 253 00:17:04,391 --> 00:17:06,124 then months. 254 00:17:06,226 --> 00:17:08,493 These elephants are on an epic rampage through 255 00:17:08,495 --> 00:17:11,729 the country, and they're leaving chaos in their wake. 256 00:17:11,731 --> 00:17:13,331 KAYS: Nothing like this has ever happened before. 257 00:17:13,333 --> 00:17:15,099 We really don't know where these elephants 258 00:17:15,101 --> 00:17:17,602 are gonna go next, we don't know what they're motivated by. 259 00:17:21,775 --> 00:17:24,542 NARRATOR: The pachyderms put authorities on high alert 260 00:17:24,644 --> 00:17:26,144 when CCTV captures 261 00:17:26,245 --> 00:17:30,014 the 11,000-pound animals barging into rural villages in 262 00:17:30,016 --> 00:17:31,115 the middle of the night. 263 00:17:33,486 --> 00:17:35,353 You can imagine these elephants are raising 264 00:17:35,455 --> 00:17:37,688 a lot of concern in the region. 265 00:17:37,690 --> 00:17:40,558 The Chinese authorities have gone as far as to leave 266 00:17:40,660 --> 00:17:43,227 truckloads of pineapples and corn 267 00:17:43,229 --> 00:17:46,998 in the path of these elephants in an attempt to lure them away 268 00:17:47,000 --> 00:17:48,933 from populated areas. 269 00:17:49,068 --> 00:17:52,103 Unfortunately, the elephants aren't really cooperating. 270 00:17:54,607 --> 00:17:57,508 NARRATOR: As they continue their bizarre march, 271 00:17:57,510 --> 00:17:59,811 the giants approach the heavily populated 272 00:17:59,813 --> 00:18:00,945 Kunming City. 273 00:18:03,016 --> 00:18:05,950 Fearing conflict between humans and the herd, 274 00:18:06,018 --> 00:18:11,055 authorities evacuate 150,000 people in their path. 275 00:18:11,124 --> 00:18:15,059 Large wild animals and human built infrastructure 276 00:18:15,128 --> 00:18:16,326 do not mix. 277 00:18:16,329 --> 00:18:19,730 This is the kind of situation that could get ugly. 278 00:18:19,732 --> 00:18:23,801 NARRATOR: Some experts worry the big-eared bulldozers are 279 00:18:23,903 --> 00:18:27,038 driven by a psychological condition known to spark 280 00:18:27,107 --> 00:18:28,306 dangerous behavior. 281 00:18:29,642 --> 00:18:31,042 There is a condition that causes 282 00:18:31,111 --> 00:18:33,945 irregular behavior in elephants known as musth. 283 00:18:36,049 --> 00:18:38,316 Musth is a natural phenomenon that we see in 284 00:18:38,451 --> 00:18:40,418 male elephants when they're getting 285 00:18:40,520 --> 00:18:42,553 into their reproductive phase. 286 00:18:43,957 --> 00:18:44,956 NARRATOR: During musth, 287 00:18:45,024 --> 00:18:47,058 an elephant's testosterone soars to 288 00:18:47,126 --> 00:18:49,460 100 times its normal levels. 289 00:18:52,065 --> 00:18:55,099 The beasts become highly aggressive, and a hormone-rich 290 00:18:55,101 --> 00:18:57,935 liquid drips from glands on the side of their heads. 291 00:18:59,305 --> 00:19:02,540 The young bull elephants are overloaded with hormones, 292 00:19:02,609 --> 00:19:05,843 and they snap into this seemingly wild, 293 00:19:05,945 --> 00:19:07,411 uncontrollable state. 294 00:19:07,547 --> 00:19:09,614 [elephant trumpets] 295 00:19:09,716 --> 00:19:11,949 When they go into musth, you never know what's gonna happen. 296 00:19:13,620 --> 00:19:16,621 NARRATOR: In the 1960s, scientists from 297 00:19:16,756 --> 00:19:18,422 the University of Oklahoma attempt 298 00:19:18,424 --> 00:19:20,958 a bizarre experiment to learn more about 299 00:19:21,060 --> 00:19:22,627 this hormone-fueled state. 300 00:19:22,629 --> 00:19:29,400 They actually tried to induce it in a captive male elephant. 301 00:19:29,402 --> 00:19:31,736 RUBEN: The problem is, they didn't know how to 302 00:19:31,837 --> 00:19:35,606 induce behavior that resembled musth in an elephant. 303 00:19:35,608 --> 00:19:37,508 They came up with a very 304 00:19:37,510 --> 00:19:42,413 1960s answer -- they gave the elephants LSD. 305 00:19:44,450 --> 00:19:47,652 KOUROUNIS: Of course, how much LSD do you give an elephant? 306 00:19:47,720 --> 00:19:51,222 None of them knew what the doses should be. 307 00:19:51,324 --> 00:19:53,424 NARRATOR: In the same era, 308 00:19:53,426 --> 00:19:56,227 during C.I.A, mind control experiments, 309 00:19:56,229 --> 00:19:59,130 soldiers feel the drug's psychedelic effect 310 00:19:59,132 --> 00:20:03,301 after a 30-microgram shot. 311 00:20:03,403 --> 00:20:05,436 Scaling up to monster size, 312 00:20:05,505 --> 00:20:08,339 they pumped the elephant with 10,000 times 313 00:20:08,408 --> 00:20:10,208 the human dose. 314 00:20:10,210 --> 00:20:12,343 RUBEN: It was not a good guess. 315 00:20:12,412 --> 00:20:16,113 The result was, immediately after being injected with LSD, 316 00:20:16,115 --> 00:20:18,549 the elephant keeled over and started having seizures. 317 00:20:18,651 --> 00:20:21,686 The researchers tried to save the elephant by injecting it 318 00:20:21,688 --> 00:20:24,121 with other drugs, but to no one's surprise, 319 00:20:24,123 --> 00:20:25,289 it didn't work. 320 00:20:25,291 --> 00:20:26,624 The animal died. 321 00:20:26,726 --> 00:20:29,026 The scientists didn't really learn anything other 322 00:20:29,028 --> 00:20:32,063 than don't inject an elephant with LSD. 323 00:20:32,164 --> 00:20:36,100 It was really just a tragic waste of an elephant. 324 00:20:36,202 --> 00:20:39,303 NARRATOR: While musth is known 325 00:20:39,305 --> 00:20:41,806 to trigger the kind of behavior seen in China, 326 00:20:41,808 --> 00:20:44,041 it appears the trip these elephants 327 00:20:44,143 --> 00:20:47,612 have taken has a different explanation. 328 00:20:47,714 --> 00:20:51,315 When you zoom in, you see baby elephants in the photos, 329 00:20:51,417 --> 00:20:54,385 which means that they are with their moms, 330 00:20:54,387 --> 00:20:57,421 and female elephants don't go into musth. 331 00:20:57,423 --> 00:20:59,323 So there must be something else going on. 332 00:21:01,060 --> 00:21:04,262 NARRATOR: Biologists uncover another possible clue 333 00:21:04,330 --> 00:21:06,264 to why the elephants have strayed 334 00:21:06,332 --> 00:21:09,333 so far from the safety of their reserve. 335 00:21:09,402 --> 00:21:12,703 Over the past 30 years, a crackdown on poaching 336 00:21:12,705 --> 00:21:15,106 has doubled wild Asian elephant numbers 337 00:21:15,108 --> 00:21:16,340 in their reserve. 338 00:21:16,442 --> 00:21:20,544 The problem is, although China has more elephants now, 339 00:21:20,613 --> 00:21:24,115 they had the same amount of protected forest habitat that 340 00:21:24,217 --> 00:21:25,950 these elephants like to live in. 341 00:21:26,085 --> 00:21:28,419 SCHUTTLER: So perhaps there's too many elephants 342 00:21:28,521 --> 00:21:31,088 for the forest, and they are forced to 343 00:21:31,090 --> 00:21:34,358 venture out and find another big patch of forest 344 00:21:34,460 --> 00:21:36,427 that they can live in. 345 00:21:36,529 --> 00:21:38,062 NARRATOR: Outside the reserve, 346 00:21:38,131 --> 00:21:40,364 new habitat is hard to find. 347 00:21:41,701 --> 00:21:44,235 Over the past seven decades, 348 00:21:44,337 --> 00:21:47,305 a Chinese building frenzy creates an average of nearly 349 00:21:47,307 --> 00:21:49,240 eight new cities a year. 350 00:21:51,344 --> 00:21:53,844 As these concrete jungles rise, 351 00:21:53,979 --> 00:21:56,514 more than 100,000 acres of forest 352 00:21:56,649 --> 00:21:58,115 are destroyed each month. 353 00:21:59,652 --> 00:22:02,920 So it's possible that this group didn't really 354 00:22:02,922 --> 00:22:05,122 want to be in the towns and villages. 355 00:22:05,124 --> 00:22:08,426 They were just looking for another forest to go to. 356 00:22:08,528 --> 00:22:09,827 KAYS: The elephants don't know where they're going. 357 00:22:09,929 --> 00:22:11,194 They don't have a map. 358 00:22:11,264 --> 00:22:13,898 They're just wandering north and exploring new territory 359 00:22:13,900 --> 00:22:17,735 and finding all sorts of food along the way. 360 00:22:17,837 --> 00:22:19,637 NARRATOR: But another surprising twist in 361 00:22:19,739 --> 00:22:23,307 the elephants' story throws this theory into doubt. 362 00:22:24,410 --> 00:22:28,813 After walking over 300 miles, they make a sudden U-turn 363 00:22:28,948 --> 00:22:30,047 and head for home. 364 00:22:31,217 --> 00:22:34,418 There's a phrase that an elephant never forgets, 365 00:22:34,420 --> 00:22:37,154 and there's actually some truth to that. 366 00:22:37,223 --> 00:22:39,824 OKEREKE: They have the largest temporal lobe out of any animal, 367 00:22:39,926 --> 00:22:41,192 including humans. 368 00:22:41,327 --> 00:22:42,426 This is part of the brain 369 00:22:42,561 --> 00:22:45,129 that deals with things like spatial memory. 370 00:22:45,231 --> 00:22:48,399 NARRATOR: This spatial memory allows Asian elephants to 371 00:22:48,501 --> 00:22:50,301 memorize home ranges 372 00:22:50,303 --> 00:22:53,070 almost double the size of New York City. 373 00:22:53,072 --> 00:22:54,905 They know their way around their territory, 374 00:22:54,907 --> 00:22:56,407 and if they leave their territory, 375 00:22:56,509 --> 00:22:58,008 they are most certainly gonna be able to 376 00:22:58,010 --> 00:22:59,610 navigate back if they want to. 377 00:23:01,447 --> 00:23:03,714 NARRATOR: Two months later, the elephants reach 378 00:23:03,816 --> 00:23:06,951 the reserve they left over one-and-a-half years ago. 379 00:23:08,254 --> 00:23:11,322 But the reason why these adventurous giants 380 00:23:11,324 --> 00:23:14,959 undertook their epic journey remains a mystery. 381 00:23:15,061 --> 00:23:17,128 KOUROUNIS: These are wild animals. 382 00:23:17,229 --> 00:23:19,330 They're gonna do what they wanna do. 383 00:23:19,332 --> 00:23:21,065 They might get home and then turn around, 384 00:23:21,133 --> 00:23:23,534 decide that they want to go walkabout again. 385 00:23:23,636 --> 00:23:24,935 It's nature. 386 00:23:30,810 --> 00:23:33,210 NARRATOR: Coming up, the strange circle 387 00:23:33,212 --> 00:23:34,912 that helped defeat Hitler. 388 00:23:34,914 --> 00:23:37,248 Its importance cannot be overstated. 389 00:23:38,418 --> 00:23:41,352 NARRATOR: And the two-million-year-old mystery. 390 00:23:41,421 --> 00:23:43,521 These might unlock a previously 391 00:23:43,623 --> 00:23:46,457 unknown chapter in humanity's earliest days. 392 00:23:54,100 --> 00:23:56,600 NARRATOR: October 2021. 393 00:23:56,602 --> 00:23:59,804 Eyes in the sky over the eastern 394 00:23:59,806 --> 00:24:03,607 United States capture this image of a New Jersey suburb. 395 00:24:07,613 --> 00:24:12,049 I'm looking at what looks like a pretty busy waterfront area, 396 00:24:12,118 --> 00:24:15,820 but then this nearly perfect circle of forested, 397 00:24:15,822 --> 00:24:17,888 undeveloped area. 398 00:24:17,890 --> 00:24:21,459 It almost seems like someone took 399 00:24:21,560 --> 00:24:25,429 like a cookie cutter, just stamped it, 400 00:24:25,431 --> 00:24:27,765 in an area that's pretty heavily populated. 401 00:24:30,036 --> 00:24:32,203 NARRATOR: Experts take a closer look. 402 00:24:33,239 --> 00:24:36,640 If we zoom in, what you can see is a railway running 403 00:24:36,709 --> 00:24:38,209 through the forested area, 404 00:24:38,311 --> 00:24:40,311 and when you follow that railway west, 405 00:24:40,313 --> 00:24:43,113 what you discover are various other structures, 406 00:24:43,216 --> 00:24:45,649 which resemble military bunkers. 407 00:24:47,220 --> 00:24:50,321 NARRATOR: Scale analysis shows the circular 408 00:24:50,423 --> 00:24:53,123 anomaly is one mile in diameter. 409 00:24:53,226 --> 00:24:55,559 To military historian Martin Morgan, 410 00:24:55,628 --> 00:24:57,862 the dimensions are hauntingly familiar. 411 00:24:59,398 --> 00:25:01,999 What we're seeing here is an exclusion zone that was 412 00:25:02,001 --> 00:25:03,100 created to prevent 413 00:25:03,102 --> 00:25:06,604 a repeat of the largest non-nuclear explosion in 414 00:25:06,706 --> 00:25:09,406 the history of the North American continent. 415 00:25:09,509 --> 00:25:13,511 NARRATOR: That explosion hit the port of Halifax, 416 00:25:13,646 --> 00:25:16,146 Nova Scotia, more than a century ago, 417 00:25:16,148 --> 00:25:21,118 while it was being used as a World War I munitions hub. 418 00:25:21,120 --> 00:25:24,555 Halifax, Nova Scotia, was one of the most critical 419 00:25:24,624 --> 00:25:27,858 transshipment points for material 420 00:25:27,927 --> 00:25:29,727 traveling to Europe. 421 00:25:29,729 --> 00:25:33,631 You had Canadian warships, American warships, 422 00:25:33,633 --> 00:25:37,902 merchant vessels, all traversing these waterways. 423 00:25:37,904 --> 00:25:42,406 It was a very fine balance of chaotic logistics. 424 00:25:42,508 --> 00:25:44,041 [boat horn blows] 425 00:25:44,110 --> 00:25:47,244 NARRATOR: On December 6, 1917, 426 00:25:47,313 --> 00:25:49,647 this chaos descends into tragedy. 427 00:25:52,318 --> 00:25:54,051 AUERBACH: Just before nine a.m. 428 00:25:54,120 --> 00:25:57,521 in the morning, a Norwegian vessel heading 429 00:25:57,523 --> 00:26:02,026 for New York strikes a French munitions ship 430 00:26:02,028 --> 00:26:04,962 that was just getting ready to head out across the Atlantic. 431 00:26:05,030 --> 00:26:09,333 The impact from the collision renders the French vessel 432 00:26:09,435 --> 00:26:11,602 essentially rudderless -- it's just adrift. 433 00:26:11,604 --> 00:26:14,605 It's also engulfed in flames. 434 00:26:14,607 --> 00:26:17,441 NARRATOR: Concealed inside the flaming ship 435 00:26:17,543 --> 00:26:21,612 are 2,500 tons of high explosives. 436 00:26:21,714 --> 00:26:25,783 There's this blinding, blinding white flash. 437 00:26:25,851 --> 00:26:29,720 [explosion blasts] 438 00:26:29,822 --> 00:26:31,922 In an instant, a huge shock wave 439 00:26:31,924 --> 00:26:34,725 rolls out from the source of the explosion. 440 00:26:34,727 --> 00:26:37,561 When the thick, yellow smoke clears, 441 00:26:37,597 --> 00:26:40,130 the true scale of the devastation becomes apparent. 442 00:26:42,168 --> 00:26:44,201 What you've got is a scene that's kind of 443 00:26:44,203 --> 00:26:45,936 beyond horrifying. 444 00:26:47,306 --> 00:26:50,274 The town -- it's in total ruin, 445 00:26:50,276 --> 00:26:52,943 and there's just fire raging everywhere. 446 00:26:54,046 --> 00:26:57,047 NARRATOR: The explosion destroys a square mile of the town, 447 00:26:58,217 --> 00:27:02,119 killing 2,000 people and injuring 9,000 more. 448 00:27:03,122 --> 00:27:04,722 It remains one of the most 449 00:27:04,724 --> 00:27:08,626 catastrophic manmade disasters in history. 450 00:27:08,728 --> 00:27:12,062 A very important lesson is to be learned from this incident, 451 00:27:12,164 --> 00:27:14,932 and the lesson relates to using 452 00:27:14,934 --> 00:27:19,103 a seaside town as a place where munitions are being 453 00:27:19,105 --> 00:27:21,739 loaded and offloaded during a time of war. 454 00:27:25,044 --> 00:27:28,312 NARRATOR: In 1943, this lesson is put into practice when 455 00:27:28,314 --> 00:27:32,416 the U.S. Navy creates a massive wartime munitions facility at 456 00:27:32,518 --> 00:27:33,717 the site in the image. 457 00:27:35,621 --> 00:27:38,989 The U.S. Navy establishes Earle Naval Weapons Station, 458 00:27:38,991 --> 00:27:42,893 and it is intended to be a facility whereby explosive 459 00:27:42,895 --> 00:27:45,429 munitions can be stored sufficiently far away 460 00:27:45,431 --> 00:27:48,799 from civilian population so that there's not a civilian 461 00:27:48,801 --> 00:27:51,201 loss of life like there was in Halifax. 462 00:27:54,206 --> 00:27:56,840 NARRATOR: At this time, many U.S. factories 463 00:27:56,942 --> 00:27:59,043 have retooled as munitions plants. 464 00:28:00,212 --> 00:28:03,414 They will manufacture 2/3 of the entire Allied 465 00:28:03,416 --> 00:28:05,149 arsenal, including 466 00:28:05,250 --> 00:28:10,454 40 billion bullets and over 1.5 million tons of bombs. 467 00:28:11,991 --> 00:28:14,725 WALTERS: These are staggering levels of production. 468 00:28:14,827 --> 00:28:16,960 At the very peak of the Second World War, 469 00:28:17,063 --> 00:28:20,798 America is manufacturing almost as many munitions 470 00:28:20,800 --> 00:28:24,034 as its allies and its enemies combined. 471 00:28:26,706 --> 00:28:29,640 NARRATOR: The Halifax explosion is a chilling reminder 472 00:28:29,709 --> 00:28:32,843 of just how dangerous transporting munitions can be. 473 00:28:34,013 --> 00:28:38,048 So engineers construct an exclusion zone at the site 474 00:28:38,117 --> 00:28:41,852 that matches the blast radius of the 1917 explosion. 475 00:28:41,987 --> 00:28:46,957 The live munitions are brought by rail into the circular 476 00:28:47,059 --> 00:28:49,326 exclusion zone, where they are then stored, 477 00:28:49,461 --> 00:28:52,763 ready for the moment when ships are ready to load. 478 00:28:52,798 --> 00:28:55,833 MORGAN: If there was a large-scale explosion, 479 00:28:55,935 --> 00:28:59,536 anyone outside of that one-mile radius, 480 00:28:59,605 --> 00:29:01,638 they'll probably survive. 481 00:29:01,740 --> 00:29:06,110 NARRATOR: As the conflict unfolds, the military funnels 482 00:29:06,112 --> 00:29:08,812 increasing amounts of munitions through the site 483 00:29:08,947 --> 00:29:12,916 to this 2.9-mile-long pier, where ships await. 484 00:29:15,821 --> 00:29:17,121 At the height of the war, 485 00:29:17,223 --> 00:29:21,558 there was just a nearly constant stream of ships laden 486 00:29:21,627 --> 00:29:26,029 with munitions, weapons, coming from the port across 487 00:29:26,031 --> 00:29:28,532 the Atlantic to support Allied forces. 488 00:29:28,601 --> 00:29:34,404 Earle's importance to the Second World War cannot be overstated. 489 00:29:34,507 --> 00:29:38,041 Almost every United States Navy warship or transport that 490 00:29:38,110 --> 00:29:39,810 sailed across the Atlantic 491 00:29:39,912 --> 00:29:42,412 carrying ammunition took that ammunition 492 00:29:42,414 --> 00:29:45,249 on board at Earle Naval Weapons Station. 493 00:29:47,920 --> 00:29:53,323 NARRATOR: During World War II, over 700,000 tons of supplies 494 00:29:53,425 --> 00:29:55,526 and munitions are stored and shipped 495 00:29:55,528 --> 00:29:56,827 through the exclusion zone. 496 00:29:57,930 --> 00:30:00,531 And while the bombs and bullets are gone, 497 00:30:00,533 --> 00:30:05,002 the mark it left on history is still evident from the sky. 498 00:30:05,004 --> 00:30:07,104 Nobody has ever been allowed to 499 00:30:07,206 --> 00:30:09,907 move into and live inside that circle. 500 00:30:09,909 --> 00:30:12,109 And that's why it continues to show up in satellite 501 00:30:12,111 --> 00:30:14,044 photography even to this day, 502 00:30:14,113 --> 00:30:16,013 80 years later. 503 00:30:23,055 --> 00:30:26,857 NARRATOR: Coming up, the wrath of the pharaohs. 504 00:30:26,926 --> 00:30:30,861 The Egyptians strike back with vengeance. 505 00:30:30,930 --> 00:30:34,565 NARRATOR: And a killer above the City of Angels. 506 00:30:34,633 --> 00:30:38,001 Finding the cause of this is literally life and death. 507 00:30:46,712 --> 00:30:49,847 NARRATOR: September 2019. 508 00:30:49,982 --> 00:30:53,250 A satellite scanning the seemingly endless 509 00:30:53,319 --> 00:30:57,654 sands of the eastern Sahara captures a mystery. 510 00:31:00,793 --> 00:31:01,925 WALTERS: It's amazing. 511 00:31:01,993 --> 00:31:06,330 There are all these dark holes cut into the desert. 512 00:31:06,398 --> 00:31:10,100 There are dozens of them, maybe even hundreds, 513 00:31:10,202 --> 00:31:12,936 in this kind of nest. 514 00:31:14,607 --> 00:31:17,241 NARRATOR: Analysts punch up the magnification. 515 00:31:18,477 --> 00:31:20,210 Zooming in, 516 00:31:20,212 --> 00:31:23,347 I can see that the holes have regular shapes. 517 00:31:23,448 --> 00:31:25,716 They're square. They're oblong. 518 00:31:25,718 --> 00:31:28,518 WALTERS: It looks to me like these marks have 519 00:31:28,520 --> 00:31:31,722 been made by someone cutting into the ground. 520 00:31:33,859 --> 00:31:36,960 NARRATOR: The weird cluster of holes sits in the Republic 521 00:31:37,095 --> 00:31:40,964 of Sudan, whose deserts have an extraordinary history 522 00:31:41,033 --> 00:31:43,533 stretching back more than 6,000 years. 523 00:31:45,404 --> 00:31:48,605 It was once the epicenter of the ancient world, 524 00:31:48,607 --> 00:31:52,042 and it got its power from a resource found under 525 00:31:52,144 --> 00:31:53,043 the desert. 526 00:31:53,112 --> 00:31:55,345 That was gold. 527 00:31:55,414 --> 00:31:59,816 What we're seeing here is an ancient gold mine. 528 00:31:59,919 --> 00:32:02,653 NARRATOR: The first kingdom to mine gold 529 00:32:02,721 --> 00:32:05,555 on a grand scale here are the Kerma, 530 00:32:05,657 --> 00:32:08,525 whose capital rises on the banks of the Nile River 531 00:32:08,627 --> 00:32:11,061 in 2500 B.C.E. 532 00:32:11,130 --> 00:32:14,164 Over the years, it became one of 533 00:32:14,233 --> 00:32:17,701 the most important, most advanced civilizations in 534 00:32:17,803 --> 00:32:19,403 the ancient world. 535 00:32:19,538 --> 00:32:22,906 The Kerma itself was the most extraordinary urban complex, 536 00:32:22,908 --> 00:32:25,943 which has really only partly been investigated by 537 00:32:26,044 --> 00:32:28,211 modern archaeologists. 538 00:32:28,347 --> 00:32:30,747 WALTERS: From this great city, 539 00:32:30,849 --> 00:32:36,219 the Kerma kingdom was able to spread across North Africa. 540 00:32:36,221 --> 00:32:38,622 NARRATOR: In 1550 B.C.E., 541 00:32:38,624 --> 00:32:40,657 driven by a lust for riches, 542 00:32:40,726 --> 00:32:44,094 the Kerma move north and invade a neighboring but even 543 00:32:44,096 --> 00:32:46,363 more powerful empire. 544 00:32:46,465 --> 00:32:50,901 The Kerma attacked gold mines owned by the Egyptian empire. 545 00:32:50,903 --> 00:32:54,404 That was a very bad idea. 546 00:32:54,406 --> 00:32:57,941 NARRATOR: The ancient Egyptians are obsessed with gold, 547 00:32:58,010 --> 00:33:01,645 believing it to be a symbol of power and immortality. 548 00:33:02,715 --> 00:33:06,149 The sort of heavenly value placed on gold means that 549 00:33:06,251 --> 00:33:10,554 when the Kerma attack, the Egyptians strike back 550 00:33:10,655 --> 00:33:11,655 with vengeance. 551 00:33:11,724 --> 00:33:14,124 [distant battle sounds] 552 00:33:14,259 --> 00:33:18,829 The Egyptians moved into the land controlled 553 00:33:18,831 --> 00:33:23,400 by Kerma, built a series of enormous fortresses, 554 00:33:23,402 --> 00:33:26,403 and exploited the gold mines themselves. 555 00:33:27,506 --> 00:33:30,407 NARRATOR: These ancient mines eventually fell silent 556 00:33:30,542 --> 00:33:32,109 in around 30 B.C.E. 557 00:33:35,014 --> 00:33:37,514 But over the past few years, there has been 558 00:33:37,516 --> 00:33:39,116 renewed activity. 559 00:33:40,819 --> 00:33:43,954 A bloody civil war, which has left Sudan divided 560 00:33:44,023 --> 00:33:47,057 and in ruin, has led to another gold rush 561 00:33:47,126 --> 00:33:48,759 in the site seen from space. 562 00:33:49,928 --> 00:33:52,729 Mining in this region increased dramatically after 563 00:33:52,831 --> 00:33:56,533 Sudan was split into two nations in 2011. 564 00:33:56,602 --> 00:34:00,637 The North Sudanese open new mines in this same 565 00:34:00,706 --> 00:34:04,508 region once explored by the Kerma and the Egyptians. 566 00:34:04,510 --> 00:34:07,110 Now, North Sudan is the second 567 00:34:07,245 --> 00:34:09,646 largest producer of gold in Africa. 568 00:34:09,748 --> 00:34:14,051 NARRATOR: In 2021, archaeologists find something 569 00:34:14,152 --> 00:34:17,621 even more valuable than gold here -- 570 00:34:17,723 --> 00:34:20,924 tools made by the ancient human species 571 00:34:20,926 --> 00:34:22,959 known as Homo erectus. 572 00:34:24,730 --> 00:34:29,299 Homo erectus is the immediate precursor to Homo sapien, 573 00:34:29,401 --> 00:34:33,203 and what was exceptional about Homo erectus is it was 574 00:34:33,205 --> 00:34:37,808 the first species of Homo that closely resembled our modern 575 00:34:37,943 --> 00:34:40,510 bodily appearance. 576 00:34:40,512 --> 00:34:43,947 NARRATOR: Homo erectus marks a giant leap in our evolution 577 00:34:44,082 --> 00:34:47,417 by becoming the first species of human to walk upright 578 00:34:48,821 --> 00:34:50,921 1.8 million years ago, 579 00:34:50,923 --> 00:34:54,524 they begin to migrate north from Africa into Eurasia, 580 00:34:56,328 --> 00:34:58,428 a journey that eventually gives rise to 581 00:34:58,430 --> 00:35:01,031 the eight billion people on Earth today. 582 00:35:03,502 --> 00:35:06,036 The tools indicate they used the site in 583 00:35:06,105 --> 00:35:08,839 the image as some kind of workshop during this 584 00:35:08,941 --> 00:35:11,141 extraordinary exodus. 585 00:35:11,210 --> 00:35:15,212 Before they became the humans of today, 586 00:35:15,214 --> 00:35:16,813 our ancestors were 587 00:35:16,915 --> 00:35:19,816 chopping stone tools, 588 00:35:19,918 --> 00:35:23,420 refining blades, in this very place. 589 00:35:23,522 --> 00:35:26,523 This is an astonishing discovery. 590 00:35:26,658 --> 00:35:29,726 NARRATOR: What's more, the location of the tools could 591 00:35:29,728 --> 00:35:30,961 dramatically change 592 00:35:31,062 --> 00:35:33,663 our understanding of the epic journey made 593 00:35:33,732 --> 00:35:35,532 by these early humans. 594 00:35:35,601 --> 00:35:37,701 NARDI: We've always assumed that people came up 595 00:35:37,703 --> 00:35:40,537 north through Ethiopia and out through Yemen, 596 00:35:40,639 --> 00:35:42,606 but what we're finding now is -- is maybe 597 00:35:42,708 --> 00:35:45,242 there is a different route out of Africa. 598 00:35:45,310 --> 00:35:47,944 NARRATOR: The deserts of Sudan could hold evidence of 599 00:35:48,013 --> 00:35:50,313 a new route our ancestors took 600 00:35:50,415 --> 00:35:52,349 on their history-defining journey. 601 00:35:53,452 --> 00:35:56,119 These mines might unlock a previously 602 00:35:56,221 --> 00:35:59,055 unknown chapter in humanity's earliest days. 603 00:36:06,431 --> 00:36:07,731 NARRATOR: Coming up, 604 00:36:07,733 --> 00:36:10,700 something weird in the skies above L.A. 605 00:36:10,702 --> 00:36:13,637 This cloud covered the entire region. 606 00:36:21,613 --> 00:36:24,047 NARRATOR: October 2021. 607 00:36:24,149 --> 00:36:26,716 The Sentinel-5P satellite flies 608 00:36:26,718 --> 00:36:30,320 over the California coast -- as it passes above 609 00:36:30,455 --> 00:36:32,856 Los Angeles, onboard instruments 610 00:36:32,958 --> 00:36:35,725 scan the skies below. 611 00:36:35,727 --> 00:36:38,061 The satellite is equipped with sensors that are capable of 612 00:36:38,163 --> 00:36:40,263 detecting gasses in the atmosphere, 613 00:36:40,332 --> 00:36:42,399 and what these satellites have picked up 614 00:36:42,401 --> 00:36:43,800 is very concerning. 615 00:36:45,470 --> 00:36:47,804 NARRATOR: When processed, the data reveals 616 00:36:47,806 --> 00:36:51,141 high volumes of nitrogen dioxide. 617 00:36:51,243 --> 00:36:54,611 This toxic pollutant gives L.A.'s infamous smog 618 00:36:54,746 --> 00:36:58,615 its orange tint, but the size and intensity 619 00:36:58,750 --> 00:37:01,518 of these plumes are on a lethal scale. 620 00:37:02,821 --> 00:37:05,755 Huge clouds of gas are enveloping the city. 621 00:37:07,059 --> 00:37:08,625 OKEREKE: This is really alarming. 622 00:37:08,760 --> 00:37:11,962 Nitrogen dioxide is a nasty gas that can cause things like 623 00:37:12,063 --> 00:37:13,530 severe respiratory illness, 624 00:37:13,532 --> 00:37:15,432 inflamed lungs. 625 00:37:15,533 --> 00:37:19,603 Finding the cause of the spike is literally life and death. 626 00:37:19,705 --> 00:37:23,406 NARRATOR: A check of local weather reports suggests 627 00:37:23,408 --> 00:37:25,942 a freak natural event could be to blame. 628 00:37:27,613 --> 00:37:30,947 Around a month before the toxic clouds are seen over 629 00:37:31,049 --> 00:37:32,215 the L.A. area, 630 00:37:32,217 --> 00:37:35,018 a massive storm hits the Californian coast 631 00:37:35,020 --> 00:37:38,788 in what is known as the Bay Area lightning event. 632 00:37:38,790 --> 00:37:42,359 [thunder crashing] 633 00:37:42,427 --> 00:37:44,160 RODRIGUEZ McROBBIE: This Bay Area lightning event 634 00:37:44,262 --> 00:37:47,197 was this string of incredibly dramatic thunderstorms 635 00:37:47,199 --> 00:37:48,865 that covered the entire region. 636 00:37:48,934 --> 00:37:52,802 It also would have produced a huge amount of 637 00:37:52,937 --> 00:37:54,938 nitrogen dioxide. 638 00:37:55,073 --> 00:37:58,541 NARRATOR: Lightning cooks up nitrogen dioxide 639 00:37:58,643 --> 00:37:59,809 by super heating the air 640 00:37:59,911 --> 00:38:02,612 to 50,000 degrees Fahrenheit, 641 00:38:02,714 --> 00:38:06,249 five times hotter than the surface of the sun. 642 00:38:06,318 --> 00:38:08,318 This is powerful enough to break 643 00:38:08,420 --> 00:38:10,820 the bonds of nitrogen molecules in the atmosphere. 644 00:38:10,822 --> 00:38:12,322 Now, once these bonds are split, 645 00:38:12,424 --> 00:38:14,824 they quickly bond with oxygen in the atmosphere to form 646 00:38:14,959 --> 00:38:17,327 nitrogen dioxide. 647 00:38:17,429 --> 00:38:19,696 NARRATOR: Each strike instantaneously 648 00:38:19,698 --> 00:38:22,932 creates up to 15 pounds of the toxic gas. 649 00:38:25,904 --> 00:38:28,938 During the Bay Area event, over 1,000 650 00:38:29,007 --> 00:38:30,807 bolts hit the ground in one night, 651 00:38:32,511 --> 00:38:35,712 along with countless cloud-to-cloud strikes. 652 00:38:35,714 --> 00:38:39,716 OKEREKE: It's very much possible that a storm like the Bay Area 653 00:38:39,718 --> 00:38:41,051 lightning event could be 654 00:38:41,119 --> 00:38:43,987 the cause of a sudden rise in nitrogen dioxide levels 655 00:38:43,989 --> 00:38:47,257 all over the Los Angeles area. 656 00:38:47,359 --> 00:38:49,959 NARRATOR: But further data captured from across the country 657 00:38:50,061 --> 00:38:53,663 suggests the killer clouds have a different origin. 658 00:38:53,765 --> 00:38:56,800 If we look at similar analysis conducted over 659 00:38:56,802 --> 00:38:59,135 New York, we see a near identical 660 00:38:59,237 --> 00:39:02,238 distribution pattern of nitrogen dioxide. 661 00:39:02,340 --> 00:39:05,041 Los Angeles and New York are both massive cities, 662 00:39:05,143 --> 00:39:08,645 huge population centers, and they're both coastal cities. 663 00:39:08,747 --> 00:39:10,647 Now we know that one of the biggest 664 00:39:10,749 --> 00:39:13,616 drivers of nitrogen dioxide emissions is burning 665 00:39:13,618 --> 00:39:14,951 fossil fuels. 666 00:39:15,053 --> 00:39:17,354 But why is this happening now? 667 00:39:18,824 --> 00:39:21,758 NARRATOR: What's more, coastal cities around the world 668 00:39:21,826 --> 00:39:25,128 are experiencing the same nitrogen dioxide surge. 669 00:39:27,532 --> 00:39:29,632 Investigations reveal the clouds are 670 00:39:29,701 --> 00:39:33,403 an unexpected consequence of the global COVID pandemic. 671 00:39:34,806 --> 00:39:39,342 This cloud of nitrogen dioxide that's hanging over L.A., 672 00:39:39,444 --> 00:39:43,246 it's just another legacy of a deadly disease 673 00:39:43,315 --> 00:39:48,351 that's already taken so much and caused so much devastation. 674 00:39:49,421 --> 00:39:52,021 NARRATOR: The events that spark the deadly spike 675 00:39:52,023 --> 00:39:54,391 begin in early 2020, 676 00:39:54,393 --> 00:39:57,727 when global lockdowns forced four billion people to stay 677 00:39:57,829 --> 00:39:59,929 at home. 678 00:39:59,931 --> 00:40:03,733 With shops and restaurants closed, U.S. consumers alone 679 00:40:03,835 --> 00:40:08,705 save up $1.6 trillion dollars and go on a shopping spree. 680 00:40:11,343 --> 00:40:13,843 A lot of people have been stuck at home, ordering things 681 00:40:13,945 --> 00:40:18,348 online, and many of these goods are shipped in from overseas. 682 00:40:18,417 --> 00:40:21,251 OKEREKE: Shipping companies are racing to meet that demand. 683 00:40:21,352 --> 00:40:23,353 The result is a lot of ships all trying 684 00:40:23,455 --> 00:40:25,522 to get into the port at the exact same time. 685 00:40:28,126 --> 00:40:30,126 NARRATOR: Off the California coast, 686 00:40:30,128 --> 00:40:34,764 queues of more than 100 container ships form, carrying 687 00:40:34,833 --> 00:40:38,034 $25 billion dollars worth of goods. 688 00:40:38,136 --> 00:40:39,602 The whole time those ships are sitting there, 689 00:40:39,604 --> 00:40:43,406 they're burning fuel and pumping out nitrogen dioxide. 690 00:40:44,443 --> 00:40:46,142 RODRIGUEZ McROBBIE: This is like when 691 00:40:46,211 --> 00:40:48,011 there's a traffic jam in a tunnel, 692 00:40:48,013 --> 00:40:51,815 and the air outside of your car is filling 693 00:40:51,917 --> 00:40:54,317 with nitrogen dioxide and fumes. 694 00:40:55,954 --> 00:40:59,856 NARRATOR: Each day, the waiting ships pump over 100 tons 695 00:40:59,991 --> 00:41:02,125 of pollution into the California air, 696 00:41:02,227 --> 00:41:05,929 the same as six million cars on the road. 697 00:41:05,931 --> 00:41:08,665 It's absolutely horrible for the local air quality to have 698 00:41:08,733 --> 00:41:12,402 these ships idling, billowing out noxious fumes 699 00:41:12,404 --> 00:41:13,603 out into the sky. 700 00:41:15,707 --> 00:41:18,608 NARRATOR: Globally, nine million people a year 701 00:41:18,610 --> 00:41:21,144 die from diseases resulting from pollution, 702 00:41:21,246 --> 00:41:23,913 20 percent of all global deaths. 703 00:41:25,417 --> 00:41:28,518 And in COVID-hit cities like L.A., 704 00:41:28,520 --> 00:41:31,921 the effect of the container ship backlog is devastating. 705 00:41:32,924 --> 00:41:34,424 RUBEN: When you think of the health impacts 706 00:41:34,526 --> 00:41:35,992 caused by COVID, you think of 707 00:41:35,994 --> 00:41:37,727 the direct deaths from the virus. 708 00:41:37,729 --> 00:41:40,897 But causing this much damage to L.A.'s air quality 709 00:41:40,899 --> 00:41:42,532 is sure to have knock-on effects. 710 00:41:43,802 --> 00:41:46,202 The noxious gasses mean that in some parts 711 00:41:46,204 --> 00:41:48,104 of the city, COVID death rates 712 00:41:48,106 --> 00:41:50,106 jump by up to 60 percent, 713 00:41:51,510 --> 00:41:54,911 another terrible legacy of this disease 714 00:41:54,913 --> 00:41:56,713 revealed from space.