1 00:00:05,130 --> 00:00:07,299 hidden from human eyes. 2 00:00:07,382 --> 00:00:11,094 Mysterious tombs, 3 00:00:11,178 --> 00:00:14,640 where mourners could speak directly to the dead. 4 00:00:14,723 --> 00:00:18,435 And caves filled with giant crystals 5 00:00:18,519 --> 00:00:22,481 that are as beautiful as they are deadly. 6 00:00:24,858 --> 00:00:29,071 For centuries, mankind has wondered, 7 00:00:29,154 --> 00:00:31,532 what lies deep beneath our feet? 8 00:00:31,615 --> 00:00:36,203 Is there a subterranean world filled with mystery and danger? 9 00:00:36,286 --> 00:00:40,332 Or one that hides untold riches? 10 00:00:40,374 --> 00:00:44,294 Perhaps even the secrets of the universe? 11 00:00:44,336 --> 00:00:49,383 Well, that is what we'll try and find out. 12 00:00:49,466 --> 00:00:51,385 ♪ ♪ 13 00:01:08,986 --> 00:01:11,488 Bordered by the Black Sea to the north 14 00:01:11,530 --> 00:01:14,992 and by the Taurus Mountains to the south, 15 00:01:15,075 --> 00:01:19,162 lies the craggy regions of Cappadocia. 16 00:01:19,246 --> 00:01:24,876 Here, wind, water, and time have sculpted the volcanic rocks 17 00:01:24,960 --> 00:01:30,007 into bizarre and almost surreal shapes. 18 00:01:30,090 --> 00:01:33,135 But believe it or not, the most unusual thing 19 00:01:33,218 --> 00:01:36,555 that was ever discovered in this otherworldly landscape 20 00:01:36,638 --> 00:01:41,184 was found not above ground, but far below. 21 00:01:43,186 --> 00:01:46,815 In 1963, during a simple home renovation 22 00:01:46,898 --> 00:01:49,026 in the town of Derinkuyu, 23 00:01:49,109 --> 00:01:53,739 a cave wall was punctured, revealing a passageway 24 00:01:53,822 --> 00:01:57,075 to what appeared to be an intricate underground city, 25 00:01:57,159 --> 00:02:02,331 thousands of years old and more than 280 feet deep. 26 00:02:04,374 --> 00:02:06,960 Derinkuyu is a pretty amazing story, 27 00:02:07,002 --> 00:02:08,587 'cause just imagine that you're working 28 00:02:08,670 --> 00:02:09,796 in your basement one day. 29 00:02:09,838 --> 00:02:10,964 You knock a hole in the wall, 30 00:02:11,006 --> 00:02:15,052 and what you find is a city that is, 31 00:02:15,135 --> 00:02:18,180 it's sort of the size of a‐a really large castle, 32 00:02:18,263 --> 00:02:20,140 but it's actually underground. 33 00:02:20,223 --> 00:02:22,142 Uh, and it was done in a time 34 00:02:22,184 --> 00:02:24,728 before there was really any mechanical means 35 00:02:24,811 --> 00:02:26,938 to provide water or ventilation, 36 00:02:27,022 --> 00:02:28,649 or any of those things. 37 00:02:28,732 --> 00:02:33,654 ANDREW COLLINS: The only thing on the surface that you can see 38 00:02:33,737 --> 00:02:36,323 are what appear to be wells. 39 00:02:36,406 --> 00:02:39,242 As you approach Derinkuyu, 40 00:02:39,326 --> 00:02:41,953 you would certainly not be aware 41 00:02:42,037 --> 00:02:45,248 that you were walking over the position 42 00:02:45,332 --> 00:02:46,708 of an underground city. 43 00:02:46,792 --> 00:02:50,712 It would have been the home for thousands of people 44 00:02:50,796 --> 00:02:55,801 at a time at some point in the distant past. 45 00:02:55,842 --> 00:02:58,637 SHATNER: Home to thousands? 46 00:02:58,679 --> 00:03:01,223 It seems hard to believe that an entire city 47 00:03:01,306 --> 00:03:03,975 could actually exist underground. 48 00:03:04,059 --> 00:03:09,147 And yet, experts claim that Derinkuyu housed 49 00:03:09,189 --> 00:03:11,650 an estimated 20,000 men, women, and children 50 00:03:11,692 --> 00:03:15,821 and included religious centers, storerooms, and living rooms. 51 00:03:15,904 --> 00:03:17,531 But how? 52 00:03:20,701 --> 00:03:24,329 MICHAEL DENNIN: Derinkuyu appears to be a combination of 53 00:03:24,371 --> 00:03:26,373 leveraging natural cave systems, 54 00:03:26,456 --> 00:03:29,292 and then building in human technology to connect it. 55 00:03:29,334 --> 00:03:32,796 And one of the things that's fascinating about this 56 00:03:32,838 --> 00:03:34,423 is the ventilation system, 57 00:03:34,506 --> 00:03:37,300 because here you're really just worried about getting air in, 58 00:03:37,342 --> 00:03:40,178 and waste like CO2 and air out. 59 00:03:40,262 --> 00:03:41,555 You're gonna be able to store water. 60 00:03:41,638 --> 00:03:43,056 If you think about how much fresh water 61 00:03:43,140 --> 00:03:44,433 is already naturally underground, 62 00:03:44,516 --> 00:03:46,977 we're constantly digging down to get to wells, 63 00:03:47,018 --> 00:03:47,978 but if you're already underground, 64 00:03:48,019 --> 00:03:49,479 the wells are right there. 65 00:03:49,563 --> 00:03:53,525 So you have the possibility of great fresh water sources. 66 00:03:55,068 --> 00:03:57,446 SHATNER: Many archeologists and scholars 67 00:03:57,529 --> 00:04:00,157 claim that Derinkuyu was most likely built 68 00:04:00,240 --> 00:04:02,659 around 800 BC by the Phrygians, 69 00:04:02,743 --> 00:04:05,829 a Bronze Age people related to the Trojans, 70 00:04:05,912 --> 00:04:08,957 and was intended to serve as a temporary shelter 71 00:04:09,040 --> 00:04:10,667 from invasion. 72 00:04:10,751 --> 00:04:15,005 But others believe it was built by the Hittites, 73 00:04:15,088 --> 00:04:17,174 a warrior people mentioned in the Bible, 74 00:04:17,257 --> 00:04:21,261 who flourished a few hundred years before that. 75 00:04:21,344 --> 00:04:25,682 BURROWS: This is in a place that's had multiple wars. 76 00:04:25,766 --> 00:04:27,476 There's conflict taking place all the time. 77 00:04:27,517 --> 00:04:28,977 And when you're above ground, 78 00:04:29,019 --> 00:04:30,562 people can see you for miles. 79 00:04:30,645 --> 00:04:33,231 You know, each night you're lighting fires 80 00:04:33,315 --> 00:04:35,484 to get some light inside the space. 81 00:04:35,525 --> 00:04:38,153 And so, that can be seen from 20 miles or more. 82 00:04:38,236 --> 00:04:42,115 Once they go below ground, they're invisible. 83 00:04:42,199 --> 00:04:46,369 JOHN BRANDENBERG: It has, uh, massive stones that can be lowered 84 00:04:46,453 --> 00:04:50,040 to block passageways that human beings 85 00:04:50,123 --> 00:04:52,042 can only go through in single file, 86 00:04:52,125 --> 00:04:53,794 making it very easy to defend. 87 00:04:53,877 --> 00:04:56,755 There are also rumors that it is connected 88 00:04:56,838 --> 00:05:01,718 by a vast tunnel system going many, many kilometers 89 00:05:01,802 --> 00:05:05,597 to other underground cities in the neighborhood. 90 00:05:05,680 --> 00:05:08,558 So, it had emergency escape routes. 91 00:05:08,642 --> 00:05:12,187 So the whole thing was a quite remarkable 92 00:05:12,270 --> 00:05:15,315 subterranean fortress. 93 00:05:15,357 --> 00:05:18,485 SHATNER: While there is evidence to suggest 94 00:05:18,527 --> 00:05:21,404 that several different cultures have used Derinkuyu 95 00:05:21,488 --> 00:05:23,156 as a fortified sanctuary 96 00:05:23,240 --> 00:05:24,991 in the centuries that have passed 97 00:05:25,075 --> 00:05:27,118 since its initial construction, 98 00:05:27,202 --> 00:05:30,622 some researchers have theorized that it is much, much older 99 00:05:30,705 --> 00:05:34,626 than mainstream archeologists think. 100 00:05:34,668 --> 00:05:36,294 And that its original architects 101 00:05:36,378 --> 00:05:40,465 had an even bigger threat in mind when they built it. 102 00:05:40,549 --> 00:05:45,428 COLLINS: The curator of Derinkuyu in Cappadocia, 103 00:05:45,512 --> 00:05:50,141 Omer Demir, had found the evidence suggesting 104 00:05:50,225 --> 00:05:52,978 that each of the different stories or levels 105 00:05:53,019 --> 00:05:54,437 would seem to have been constructed 106 00:05:54,521 --> 00:05:57,482 by different cultures at different times. 107 00:05:57,566 --> 00:05:59,734 And what he found was incredible. 108 00:05:59,818 --> 00:06:02,988 For he discovered that there were tools, 109 00:06:03,071 --> 00:06:05,824 stone tools here, that dated back 110 00:06:05,907 --> 00:06:07,325 to Paleolithic times. 111 00:06:07,409 --> 00:06:10,954 The implications of this are enormous, 112 00:06:11,037 --> 00:06:14,541 because what this suggests is that Derinkuyu goes back 113 00:06:14,624 --> 00:06:17,961 at least 12,000 years, 114 00:06:18,044 --> 00:06:22,507 and was present at the end of the last Ice Age; 115 00:06:22,591 --> 00:06:28,471 and may well have been a place where our ancestors 116 00:06:28,513 --> 00:06:32,392 sought refuge at the time of a cataclysm, 117 00:06:32,475 --> 00:06:35,270 a cataclysm that may well have devastated 118 00:06:35,353 --> 00:06:37,230 large parts of the Earth 119 00:06:37,314 --> 00:06:41,067 at the very end of the Paleolithic era. 120 00:06:41,151 --> 00:06:44,487 SHATNER: A cataclysm? 121 00:06:44,529 --> 00:06:46,740 Could it be that the original inhabitants 122 00:06:46,823 --> 00:06:51,369 of Derinkuyu built it as a shelter to protect them 123 00:06:51,453 --> 00:06:54,581 during the Earth's last great Ice Age? 124 00:06:54,664 --> 00:06:56,917 A time when the Earth's climate was estimated to be 125 00:06:57,000 --> 00:07:00,170 more than 10 degrees colder than it is now? 126 00:07:00,253 --> 00:07:03,131 So cold that hardly anything could grow, 127 00:07:03,214 --> 00:07:06,676 or even survive, above ground? 128 00:07:06,760 --> 00:07:09,554 DENNIN: When you build your city underground, 129 00:07:09,638 --> 00:07:12,974 you get two major off‐the‐top advantages, 130 00:07:13,058 --> 00:07:14,434 one sort of environmental. 131 00:07:14,517 --> 00:07:16,561 You're gonna have great thermal properties. 132 00:07:16,645 --> 00:07:18,271 It's gonna be cool when you need it to be cool, 133 00:07:18,355 --> 00:07:20,023 but it won't get too cold, 134 00:07:20,106 --> 00:07:23,860 so it'll be kind of warm enough when you need it to be warm. 135 00:07:23,944 --> 00:07:26,863 Thinking about when this was built and inhabited 136 00:07:26,947 --> 00:07:30,450 really remains this exciting, mysterious, open question. 137 00:07:30,533 --> 00:07:33,286 Even this idea of other cities underground, 138 00:07:33,370 --> 00:07:34,621 like, how common was that 139 00:07:34,704 --> 00:07:37,374 for humans to build their homes underground, 140 00:07:37,457 --> 00:07:39,584 versus on the surface of the ground? 141 00:07:39,668 --> 00:07:43,046 Derinkuyu was rediscovered 142 00:07:43,129 --> 00:07:46,049 during the 1960s by accident. 143 00:07:46,132 --> 00:07:48,218 And there are still areas of it 144 00:07:48,301 --> 00:07:50,387 that have not been explored to this day. 145 00:07:50,470 --> 00:07:54,349 So the implications of this are incredible. 146 00:07:54,432 --> 00:07:56,559 It does feel like we've just really 147 00:07:56,643 --> 00:07:59,229 scratched the surface of what could be below us. 148 00:07:59,312 --> 00:08:00,647 There could be much more. 149 00:08:00,730 --> 00:08:04,484 There could be many more of these cave systems in Turkey. 150 00:08:04,567 --> 00:08:06,277 So there's mysteries still to be found 151 00:08:06,361 --> 00:08:08,113 deep within the Earth. 152 00:08:09,906 --> 00:08:13,159 SHATNER: The truth is, we may never know for sure why, 153 00:08:13,243 --> 00:08:16,496 or even how these ancient underground cities were built. 154 00:08:16,579 --> 00:08:19,207 And that's especially true in the case of Derinkuyu; 155 00:08:19,290 --> 00:08:23,003 because the secrets of its construction techniques 156 00:08:23,086 --> 00:08:28,008 seem to have disappeared, along with whoever built it. 157 00:08:28,091 --> 00:08:31,761 BURROWS: Even today, with all of the modern technology 158 00:08:31,845 --> 00:08:34,639 that we have, it would be incredibly complicated 159 00:08:34,681 --> 00:08:37,600 and a massive undertaking to do something like that. 160 00:08:37,684 --> 00:08:39,477 And sometimes, we look at these ancient marvels, 161 00:08:39,519 --> 00:08:42,480 and we try and figure out, could we build that today, 162 00:08:42,564 --> 00:08:44,190 to that level of accuracy, 163 00:08:44,274 --> 00:08:46,526 that sort of quality of construction 164 00:08:46,609 --> 00:08:47,819 in that amount of time? 165 00:08:47,902 --> 00:08:50,363 And the answer's no, which is pretty amazing 166 00:08:50,447 --> 00:08:54,117 that several thousand years later, they're better than us. 167 00:08:54,200 --> 00:08:58,580 SHATNER: Is it possible the builders of Derinkuyu 168 00:08:58,663 --> 00:09:00,665 knew something we don't? 169 00:09:00,749 --> 00:09:03,126 Not merely about constructing cities 170 00:09:03,209 --> 00:09:04,711 deep within the Earth, 171 00:09:04,794 --> 00:09:07,547 but about humanity's need for such refuges 172 00:09:07,630 --> 00:09:09,841 in order to survive? 173 00:09:09,924 --> 00:09:13,762 It's a fascinating, and perhaps, slightly unnerving prospect. 174 00:09:13,845 --> 00:09:17,724 Not unlike another underground structure, 175 00:09:17,807 --> 00:09:21,478 one that exists in order to maintain communication 176 00:09:21,519 --> 00:09:24,898 after the end of civilization itself. 177 00:09:31,071 --> 00:09:33,782 NICK REDFERN: In the event of an attack, it's believed the United States 178 00:09:33,865 --> 00:09:37,243 it's not difficult to believe the United States government 179 00:09:37,327 --> 00:09:38,912 has a closet full of secrets. 180 00:09:38,995 --> 00:09:43,458 But what could be so secret that they feel the need 181 00:09:43,541 --> 00:09:47,462 to keep it hidden so far underground? 182 00:09:47,545 --> 00:09:52,634 Area 51 is the world's most secret installation. 183 00:09:52,675 --> 00:09:56,304 Historically, we know that it was used 184 00:09:56,387 --> 00:09:59,474 for the testing of early spy planes, 185 00:09:59,516 --> 00:10:04,813 like the U‐2 and the SR‐71 Blackbird. 186 00:10:04,896 --> 00:10:07,982 A number of whistleblowers have come forward 187 00:10:08,024 --> 00:10:11,027 claiming to have seen levels up to about 188 00:10:11,111 --> 00:10:14,614 seven or eight levels, um, deep below the desert, 189 00:10:14,697 --> 00:10:19,035 protecting whatever's really going on at Area 51. 190 00:10:20,578 --> 00:10:25,333 TAYLOR: If there are these large tunnels and pathways under Area 51, 191 00:10:25,375 --> 00:10:28,628 so many people would have to cooperate in building it 192 00:10:28,670 --> 00:10:30,463 that'd be difficult keeping it a secret. 193 00:10:30,505 --> 00:10:32,799 But you could also ask the question, 194 00:10:32,882 --> 00:10:36,136 when was the last time you paid any attention 195 00:10:36,177 --> 00:10:38,638 to a new subway tunnel being, uh, constructed 196 00:10:38,721 --> 00:10:40,306 under the city in which you live? 197 00:10:40,390 --> 00:10:42,976 You probably never paid attention to it. 198 00:10:43,059 --> 00:10:45,186 So, it could be built right under your nose 199 00:10:45,270 --> 00:10:48,356 and you would never know it‐‐ or care, for that matter. 200 00:10:53,069 --> 00:10:55,697 SHATNER: Deep beneath these snowy peaks, 201 00:10:55,780 --> 00:10:58,992 encased within thousands of tons of solid granite, 202 00:10:59,075 --> 00:11:02,579 lies the most sophisticated and impenetrable 203 00:11:02,662 --> 00:11:06,374 military installation in the world. 204 00:11:06,457 --> 00:11:10,295 The Cheyenne Mountain Complex was built, uh, in the '60s 205 00:11:10,336 --> 00:11:12,630 and was operational in 1967. 206 00:11:12,672 --> 00:11:16,634 And the idea was that you have all of your information 207 00:11:16,676 --> 00:11:19,095 for our national missile defense 208 00:11:19,179 --> 00:11:23,183 and offense capabilities to be operated from there. 209 00:11:23,266 --> 00:11:27,187 So it had to be able to withstand major natural 210 00:11:27,270 --> 00:11:31,065 and man‐made disasters such as a nuclear attack. 211 00:11:31,149 --> 00:11:34,611 So, the Air Force and Army and Navy, 212 00:11:34,694 --> 00:11:37,864 all of the services, they were in there. 213 00:11:37,947 --> 00:11:42,827 Basically, it was the nexus of our Cold War defense center. 214 00:11:42,869 --> 00:11:47,832 REDFERN: The Cold War was at its height, and for that reason, 215 00:11:47,916 --> 00:11:51,753 it demonstrated why we had the need 216 00:11:51,836 --> 00:11:56,257 to have these kind of facilities deeply below ground, 217 00:11:56,341 --> 00:12:01,804 to allow them to hopefully survive a nuclear attack 218 00:12:01,888 --> 00:12:04,891 if the worst scenario ever happened. 219 00:12:06,768 --> 00:12:08,853 SHATNER: Originally built for a staggering cost 220 00:12:08,937 --> 00:12:13,900 of almost $150 million, or over one billion today, 221 00:12:13,983 --> 00:12:18,863 the Cheyenne Mountain Complex spans an incredible five acres 222 00:12:18,947 --> 00:12:22,200 and contains 13 three‐story buildings 223 00:12:22,283 --> 00:12:25,203 capable of housing up to 2,000 personnel, 224 00:12:25,286 --> 00:12:28,998 independent power, heating and cooling systems, 225 00:12:29,040 --> 00:12:32,126 a lake that serves as a reservoir 226 00:12:32,168 --> 00:12:36,631 and 25‐ton blast doors capable of withstanding the force 227 00:12:36,714 --> 00:12:40,426 of a 30‐megaton nuclear explosion. 228 00:12:40,510 --> 00:12:43,638 TAYLOR: If there was a nuclear attack, a direct hit, 229 00:12:43,721 --> 00:12:45,807 Cheyenne Mountain was deep enough 230 00:12:45,890 --> 00:12:48,351 that you would not be dry‐roasted. 231 00:12:48,434 --> 00:12:50,144 You would survive the heat. 232 00:12:50,186 --> 00:12:53,648 Then you got gamma rays and radioactive fallout, 233 00:12:53,690 --> 00:12:57,402 but the best protection is material. 234 00:12:57,485 --> 00:12:59,445 Dirt, earth, rocks. 235 00:12:59,529 --> 00:13:02,156 All these things are gonna protect you from that. 236 00:13:02,240 --> 00:13:05,201 SHATNER: The Cheyenne Mountain Complex 237 00:13:05,285 --> 00:13:06,828 was so central 238 00:13:06,911 --> 00:13:08,830 to the United States government's survival plans 239 00:13:08,913 --> 00:13:10,915 that they eventually realized 240 00:13:10,999 --> 00:13:15,712 it may not actually be a good idea for it to be so isolated. 241 00:13:15,795 --> 00:13:18,548 Let's say, in a worst‐case scenario, 242 00:13:18,631 --> 00:13:23,219 that Washington D. C. gets taken out by a nuclear weapon. 243 00:13:23,303 --> 00:13:26,639 Well, one of the theories is that the president and all 244 00:13:26,681 --> 00:13:32,145 of his staff would quickly be taken to the Denver Airport. 245 00:13:32,228 --> 00:13:37,317 The Denver Airport not being too far from Cheyenne Mountain, 246 00:13:37,400 --> 00:13:41,988 it would make great sense to have a tunnel rail system 247 00:13:42,071 --> 00:13:46,200 deep below the nation which potentially could go 248 00:13:46,284 --> 00:13:50,830 from Cheyenne Mountain straight through to the Denver Airport. 249 00:13:50,872 --> 00:13:52,665 When they were building that airport, 250 00:13:52,749 --> 00:13:54,000 there was this massive‐‐ 251 00:13:54,042 --> 00:13:56,711 and I mean massive‐‐ hole in the ground. 252 00:13:56,794 --> 00:13:59,005 And buildings were going up in there. 253 00:13:59,088 --> 00:14:01,424 Buildings that, all of a sudden, you know, 254 00:14:01,507 --> 00:14:03,926 you‐you didn't see them when the airport was finished. 255 00:14:04,010 --> 00:14:06,137 And their answer to that was, "Well, 256 00:14:06,220 --> 00:14:08,806 "the buildings were incorrect, and we had such a big hole, 257 00:14:08,848 --> 00:14:11,476 we just covered them over and kept building." 258 00:14:11,559 --> 00:14:13,227 W‐Who would buy that? 259 00:14:13,311 --> 00:14:19,233 REDFERN: When the airport was being constructed in 1995, 260 00:14:19,317 --> 00:14:24,530 some of the staff who were working on the facility itself, 261 00:14:24,614 --> 00:14:26,866 construction staff, engineers, 262 00:14:26,949 --> 00:14:30,119 they claimed to have seen what appeared to be 263 00:14:30,203 --> 00:14:34,832 large tunneling devices, and also, large tunnels, 264 00:14:34,916 --> 00:14:38,044 which shouldn't really have been there. 265 00:14:38,127 --> 00:14:43,216 A lot of people theorize that there is something to this deal 266 00:14:43,299 --> 00:14:46,135 about Denver Airport because an airport 267 00:14:46,177 --> 00:14:50,056 is an extremely secure location on the surface. 268 00:14:50,139 --> 00:14:52,725 You can't just walk in and go anywhere you want. 269 00:14:52,809 --> 00:14:56,354 That's good if you're hiding stuff underground. 270 00:14:58,106 --> 00:15:01,150 SHATNER: Could the United States government actually be operating 271 00:15:01,192 --> 00:15:05,154 a top‐secret tunnel system whose epicenter is beneath 272 00:15:05,238 --> 00:15:06,864 one of the largest transportation hubs 273 00:15:06,948 --> 00:15:08,324 in the country? 274 00:15:08,366 --> 00:15:12,620 According to some experts, the answer is yes. 275 00:15:12,703 --> 00:15:17,458 And that may only be the tip of the proverbial iceberg. 276 00:15:17,542 --> 00:15:21,921 REDFERN: For strategic means, it's believed the United States 277 00:15:22,004 --> 00:15:25,967 has numerous underground facilities 278 00:15:26,008 --> 00:15:28,302 which, essentially, have been bored out 279 00:15:28,344 --> 00:15:32,473 with these gigantic boring machines to create tunnels 280 00:15:32,515 --> 00:15:37,562 to essentially take people all across the United States 281 00:15:37,645 --> 00:15:40,022 in the event of an attack. 282 00:15:40,106 --> 00:15:43,609 We're talking about trains deep under the surface 283 00:15:43,693 --> 00:15:47,071 to essentially go from the east coast to the west coast 284 00:15:47,155 --> 00:15:48,948 to the north to the south 285 00:15:49,031 --> 00:15:55,163 to hide from the attacks that might be going on. 286 00:15:55,246 --> 00:15:57,999 There has been a great advance, just in civilian 287 00:15:58,040 --> 00:16:01,794 and openly‐known abilities to dig tunnels. 288 00:16:01,878 --> 00:16:04,839 This is being taken advantage of by Elon Musk 289 00:16:04,922 --> 00:16:08,050 and his Hyperloop concept, that we can create 290 00:16:08,134 --> 00:16:12,513 long‐distance underground transportation systems. 291 00:16:12,597 --> 00:16:15,933 So we can only imagine what has been accomplished 292 00:16:16,017 --> 00:16:20,271 in the secretive world of the U. S. military. 293 00:16:21,522 --> 00:16:24,817 SHATNER: But as profound and disturbing as is the notion 294 00:16:24,859 --> 00:16:29,530 of a vast network of underground bases and secret tunnels, 295 00:16:29,614 --> 00:16:32,158 there are some underground worlds that are formed 296 00:16:32,241 --> 00:16:36,078 not by man but by nature. 297 00:16:36,162 --> 00:16:38,998 And in at least one case, 298 00:16:39,040 --> 00:16:42,293 the formation is so beautiful 299 00:16:42,376 --> 00:16:46,088 that it's easy to forget that, just like mankind, 300 00:16:46,172 --> 00:16:50,468 Mother Nature can also be deadly. 301 00:17:00,019 --> 00:17:02,980 TAYLOR: FIn the mineral‐rich towne gotten aof Naica, they are, 302 00:17:03,064 --> 00:17:06,067 more than 1,000 feet below the surface of the Earth, 303 00:17:06,150 --> 00:17:08,945 a group of miners drilling through a cave wall 304 00:17:09,028 --> 00:17:11,948 make a remarkable discovery. 305 00:17:12,031 --> 00:17:14,283 Not of precious metals, 306 00:17:14,367 --> 00:17:18,371 but something far more wonderous and mysterious. 307 00:17:20,373 --> 00:17:25,294 A glittering cavern, untouched for half a million years, 308 00:17:25,378 --> 00:17:28,214 filled with the largest crystals ever found. 309 00:17:28,297 --> 00:17:30,216 TAYLOR: It's amazing. 310 00:17:30,299 --> 00:17:33,469 There are crystals that are huge. 311 00:17:33,511 --> 00:17:35,429 So big you can actually walk across them. 312 00:17:35,513 --> 00:17:38,975 And for these crystals to have gotten as big as they are, 313 00:17:39,058 --> 00:17:40,226 they had to have been growing for hundreds 314 00:17:40,309 --> 00:17:43,104 of thousands of years. 315 00:17:43,187 --> 00:17:45,690 It's a fascinating location. 316 00:17:45,815 --> 00:17:50,152 This is something you would think would only exist 317 00:17:50,194 --> 00:17:53,823 in the world of science fiction and fantasy, 318 00:17:53,906 --> 00:17:58,244 but the fact is, it's all too real. 319 00:17:59,745 --> 00:18:03,541 SHATNER: Measuring up to an astonishing 40 feet in length 320 00:18:03,624 --> 00:18:08,004 and weighing as much as 55 tons, the giant beams 321 00:18:08,129 --> 00:18:12,675 are the purest form of selenite crystal in the world. 322 00:18:12,758 --> 00:18:16,804 Crystals are the most orderly structure in nature, 323 00:18:16,846 --> 00:18:21,892 and they have the ability to absorb frequency and energy 324 00:18:21,976 --> 00:18:24,145 from objects around them. 325 00:18:24,270 --> 00:18:31,068 Now, it is my theory that these giant pylons have the ability 326 00:18:31,193 --> 00:18:35,323 to transmit and receive information and light. 327 00:18:35,448 --> 00:18:40,953 SHATNER: Only a few months after its discovery, a team of scientists 328 00:18:41,037 --> 00:18:45,291 was sent in to study this geological anomaly. 329 00:18:45,374 --> 00:18:49,003 They soon learned that Naica's Crystal Cave may be 330 00:18:49,086 --> 00:18:52,965 not only beautiful but deadly. 331 00:18:53,049 --> 00:18:58,220 TAYLOR: It's 90% to 100% relative humidity inside this cave. 332 00:18:58,346 --> 00:19:01,724 And it's always over 113 degrees Fahrenheit. 333 00:19:01,807 --> 00:19:04,143 You might think, "Well, 113 degrees isn't that bad. 334 00:19:04,226 --> 00:19:05,811 "It gets 140 degrees 335 00:19:05,895 --> 00:19:09,065 in the deserts in Iraq all the time and people live there," 336 00:19:09,148 --> 00:19:12,943 but the relative humidity in those deserts is 10%. 337 00:19:13,027 --> 00:19:16,072 In this cave, there's so much humidity, 338 00:19:16,155 --> 00:19:19,575 you can't sweat and cool your body off. 339 00:19:20,993 --> 00:19:23,788 HUTCHISON: I received an invitation to go 340 00:19:23,871 --> 00:19:28,542 on an expedition and exploration of these giant crystals. 341 00:19:28,626 --> 00:19:32,213 I was aware of the heat and humidity, 342 00:19:32,296 --> 00:19:34,090 but nothing prepared me 343 00:19:34,173 --> 00:19:37,885 for what hit me when I entered those caves. 344 00:19:38,010 --> 00:19:41,681 I felt like I was hit by a tsunami 345 00:19:41,764 --> 00:19:45,851 of tremendous heat and humidity. 346 00:19:45,935 --> 00:19:49,355 I started shaking, I was scared. 347 00:19:49,438 --> 00:19:52,316 These are near‐fatal conditions. 348 00:19:52,400 --> 00:19:56,237 SHATNER: Due to the Crystal Cave's lethal atmosphere, 349 00:19:56,320 --> 00:19:58,280 the research team was restricted 350 00:19:58,364 --> 00:20:01,951 to ten‐minute exposures to avoid being cooked alive. 351 00:20:02,034 --> 00:20:06,455 For gemologist Leela Hutchinson, the most unexpected discovery 352 00:20:06,539 --> 00:20:11,335 wasn't something she saw but something she heard. 353 00:20:11,419 --> 00:20:16,549 HUTCHISON: One of the things that I realized as I had to focus 354 00:20:16,632 --> 00:20:21,262 so intensely to keep my wits about me, 355 00:20:21,345 --> 00:20:25,933 was this ability to hear a low hum. 356 00:20:26,016 --> 00:20:28,144 (low hum sounding) 357 00:20:31,188 --> 00:20:33,441 And I thought that was very strange. 358 00:20:33,524 --> 00:20:35,317 I didn't know if it was the machinery 359 00:20:35,443 --> 00:20:37,528 that were in the tunnels 360 00:20:37,611 --> 00:20:41,741 or if it was something that might be in the cave itself. 361 00:20:43,200 --> 00:20:47,079 And later I realized, could this have been 362 00:20:47,163 --> 00:20:51,167 extremely low‐frequency resonating in there? 363 00:20:51,292 --> 00:20:54,170 Nikola Tesla was quoted as once saying 364 00:20:54,253 --> 00:20:57,548 that "we may not understand the growth of a crystal, 365 00:20:57,631 --> 00:21:02,636 but nonetheless, it is a living being." 366 00:21:03,846 --> 00:21:08,476 SHATNER: Energy from living, giant crystals? 367 00:21:08,601 --> 00:21:11,312 In an attempt to navigate the unusual properties 368 00:21:11,437 --> 00:21:14,231 of the crystals within the Naica cave, 369 00:21:14,356 --> 00:21:17,026 NASA developed special cooling equipment 370 00:21:17,109 --> 00:21:20,696 allowing scientists to withstand the cave's lethal conditions 371 00:21:20,780 --> 00:21:23,574 for as much as 30 minutes at a time. 372 00:21:23,657 --> 00:21:28,913 And according to their research, the hum emanating 373 00:21:28,996 --> 00:21:31,874 from the Crystal Cave may not be because its crystals 374 00:21:31,957 --> 00:21:35,169 are storing energy, but because they're harboring 375 00:21:35,294 --> 00:21:39,632 something even more unexpected: life. 376 00:21:39,757 --> 00:21:44,011 HUTCHINSON: In the 2008 expedition, the NASA scientists 377 00:21:44,094 --> 00:21:48,224 went into the caves and drew out fluid inclusions 378 00:21:48,307 --> 00:21:50,392 in the largest crystals, 379 00:21:50,518 --> 00:21:56,357 and found microbes that are considered to be extremophiles. 380 00:21:56,440 --> 00:21:59,735 Microbes that are living organisms. 381 00:21:59,819 --> 00:22:04,156 They're single‐celled, and they have the ability 382 00:22:04,240 --> 00:22:08,494 to survive and thrive in extreme environments. 383 00:22:08,577 --> 00:22:13,666 One of the interesting things about the extremophiles was 384 00:22:13,791 --> 00:22:15,918 there is nothing in our genetic database 385 00:22:16,001 --> 00:22:20,923 that comes close to what these extremophiles are. 386 00:22:22,716 --> 00:22:26,762 SHATNER: Microbes unlike anything seen on Earth. 387 00:22:26,846 --> 00:22:31,141 NASA's astrobiology report suggests these extremophiles 388 00:22:31,183 --> 00:22:33,519 are up to 50,000 years old, 389 00:22:33,602 --> 00:22:35,938 and could survive on other planets. 390 00:22:36,021 --> 00:22:39,483 But many wonder: is there a risk involved in handling 391 00:22:39,567 --> 00:22:42,945 these never‐before‐seen organisms? 392 00:22:43,028 --> 00:22:46,907 The Cave of the Crystals can be a dangerous place. 393 00:22:48,450 --> 00:22:50,828 For example, not long after it was found, 394 00:22:50,911 --> 00:22:55,291 one of the workers actually snuck back into the cave. 395 00:22:55,374 --> 00:22:59,545 Not surprisingly, he passed out and died. 396 00:23:00,838 --> 00:23:04,967 Now, it's unclear if he died from the air quality, 397 00:23:05,050 --> 00:23:06,468 the heat, the humidity. 398 00:23:06,552 --> 00:23:09,305 Or could it have been the extremophile microorganisms 399 00:23:09,346 --> 00:23:11,557 that were in there? 400 00:23:13,309 --> 00:23:15,936 Will we ever find out whether the giant crystals 401 00:23:16,020 --> 00:23:19,815 in the Naica cave hold the key to understanding 402 00:23:19,857 --> 00:23:22,484 the origins of life? 403 00:23:22,610 --> 00:23:26,113 Or is this one underground mystery that is simply 404 00:23:26,196 --> 00:23:30,659 too dangerous for us to investigate? 405 00:23:30,743 --> 00:23:32,745 Perhaps. 406 00:23:32,870 --> 00:23:36,457 But not all underground worlds are meant to help us understand 407 00:23:36,540 --> 00:23:38,250 the mysteries of life. 408 00:23:38,334 --> 00:23:41,337 Some actually appear to be constructed 409 00:23:41,462 --> 00:23:44,632 to bring us closer... 410 00:23:44,673 --> 00:23:48,594 to what happens to us after we die. 411 00:23:56,352 --> 00:23:58,479 SHATNER: While excavating an area LINDA ENEIX: It's extraordinary. 412 00:23:58,520 --> 00:24:00,773 for a new housing development 413 00:24:00,856 --> 00:24:04,068 just off the eastern coast of this tiny Mediterranean island, 414 00:24:04,151 --> 00:24:07,947 construction workers encounter something unexpected 415 00:24:08,030 --> 00:24:10,824 and quite unusual beneath their work site. 416 00:24:10,908 --> 00:24:16,664 A prehistoric structure, hewn from solid limestone, 417 00:24:16,747 --> 00:24:20,501 dating back more than 5,000 years. 418 00:24:20,584 --> 00:24:24,630 Upon further inspection, archaeologists soon realize 419 00:24:24,713 --> 00:24:27,591 that what the unwitting workers have unearthed 420 00:24:27,675 --> 00:24:30,302 isn't merely a lost underground temple 421 00:24:30,386 --> 00:24:31,804 or ancient sanctuary, 422 00:24:31,887 --> 00:24:36,642 but a massive subterranean necropolis. 423 00:24:36,725 --> 00:24:42,481 The Hypogeum of Hal Saflieni. 424 00:24:42,564 --> 00:24:45,567 The Malta Hypogeum is an architectural wonder 425 00:24:45,651 --> 00:24:47,111 of the ancient world. 426 00:24:47,194 --> 00:24:51,657 It was carved using primarily stone and bone tools 427 00:24:51,740 --> 00:24:53,993 by an ancient population that lived on Malta 428 00:24:54,076 --> 00:24:55,828 thousands of years ago. 429 00:24:55,869 --> 00:25:02,376 So, it's actually older than the pyramids of Egypt or Stonehenge. 430 00:25:02,459 --> 00:25:04,586 "Hypogeum" is basically a word that comes 431 00:25:04,670 --> 00:25:08,966 from the Greek terms for "cavity" or "space underground." 432 00:25:09,049 --> 00:25:11,760 It extends on three different stories 433 00:25:11,844 --> 00:25:14,888 about seven‐point‐some meters below ground. 434 00:25:14,972 --> 00:25:19,727 It covers an area of about 5,400 square feet. 435 00:25:19,810 --> 00:25:23,480 Malta's Hypogeum is, you know, one of those great examples 436 00:25:23,564 --> 00:25:27,484 of, uh, beautiful geometry, uh, underground. 437 00:25:27,568 --> 00:25:29,987 So, the geometry isn't by accident. 438 00:25:30,070 --> 00:25:32,990 It was done by somebody who knows what they were doing. 439 00:25:33,073 --> 00:25:34,324 And it looks to me, like, 440 00:25:34,408 --> 00:25:36,243 you know, this was done for a purpose. 441 00:25:37,369 --> 00:25:38,912 SHATNER: A purpose? 442 00:25:38,996 --> 00:25:41,498 Although no one knows for certain who originally built 443 00:25:41,540 --> 00:25:44,126 the Malta Hypogeum or why, 444 00:25:44,209 --> 00:25:46,962 the bones of more than 7,000 souls 445 00:25:47,004 --> 00:25:51,717 line its intricate labyrinth of corridors and alcoves. 446 00:25:51,800 --> 00:25:54,762 So, according to logic, 447 00:25:54,845 --> 00:25:59,808 it is exactly what it appears to be: an ancient burial site. 448 00:25:59,850 --> 00:26:05,939 But logic alone may not be at play here. 449 00:26:06,023 --> 00:26:09,777 There is a very intriguing room in the Hypogeum, 450 00:26:09,860 --> 00:26:11,487 which is in the middle level, uh, 451 00:26:11,528 --> 00:26:13,072 that is called the Oracle Room. 452 00:26:13,155 --> 00:26:16,658 And this Oracle Room is basically a resonance chamber. 453 00:26:16,742 --> 00:26:19,328 And it's designed, so it would seem, 454 00:26:19,411 --> 00:26:23,332 to amplify any acoustic sound waves. 455 00:26:23,415 --> 00:26:26,585 So, even by whispering, for example, 456 00:26:26,668 --> 00:26:29,088 uh, the design of the room amplifies this 457 00:26:29,171 --> 00:26:33,884 and‐and makes it into a very loud baritone sound. 458 00:26:33,967 --> 00:26:36,637 KREISBERG: The Oracle chamber itself 459 00:26:36,678 --> 00:26:39,515 appears to have been carved specifically 460 00:26:39,598 --> 00:26:42,810 to allow sound frequencies to travel, 461 00:26:42,851 --> 00:26:46,939 and the ceiling of the Oracle chamber 462 00:26:47,022 --> 00:26:50,192 actually appears to have been carved to direct sound. 463 00:26:50,275 --> 00:26:51,985 There are also niches that have been carved 464 00:26:52,069 --> 00:26:54,113 in the sides of the Oracle chamber that seem 465 00:26:54,196 --> 00:26:59,660 to be a way to produce echoes and were also created, 466 00:26:59,743 --> 00:27:02,412 in a way, to tune it to the right frequency. 467 00:27:02,496 --> 00:27:04,540 So, there was a sophistication there 468 00:27:04,623 --> 00:27:07,334 that, you know, is unexpected. 469 00:27:07,417 --> 00:27:11,130 SHATNER: In 2014, while conducting a series of experiments 470 00:27:11,213 --> 00:27:14,007 in an attempt to understand the design elements 471 00:27:14,091 --> 00:27:17,427 behind the Hypogeum's unusual acoustics, 472 00:27:17,511 --> 00:27:18,971 scientists discovered 473 00:27:19,012 --> 00:27:23,350 an unexpected and hair‐raising phenomenon. 474 00:27:23,433 --> 00:27:26,979 KREISBERG: We set up microphones and we used recording devices 475 00:27:27,062 --> 00:27:30,232 that were very sensitive, and we carried out experiments 476 00:27:30,315 --> 00:27:35,529 using the human voice in that 110 to 112, uh, hertz range. 477 00:27:35,612 --> 00:27:39,032 So, these are very low, guttural, bass sounds, 478 00:27:39,116 --> 00:27:43,954 and they reverberate in a very strong way within these temples. 479 00:27:44,788 --> 00:27:46,999 (low‐pitched, resonant vocalizations) 480 00:28:11,565 --> 00:28:12,816 ENEIX: I‐It's extraordinary. 481 00:28:12,900 --> 00:28:15,027 It's like being inside of a bell. 482 00:28:15,110 --> 00:28:17,946 And those vibrations are felt inside your body. 483 00:28:18,030 --> 00:28:20,991 You feel it in your tissue, you feel it in your bones. 484 00:28:21,074 --> 00:28:23,994 It can raise the hair off the back of your neck. 485 00:28:24,077 --> 00:28:28,624 Imagine going there to this dark and spooky underground place 486 00:28:28,707 --> 00:28:32,294 5,000 years ago, with this weird, eerie sound 487 00:28:32,336 --> 00:28:35,631 going on around you and‐and knowing that there are bones 488 00:28:35,672 --> 00:28:38,842 and‐‐ the whole thing is creepy now. 489 00:28:40,469 --> 00:28:44,848 PAUL DEVEREUX: It clearly was‐‐ some sort of ritual activity went on there. 490 00:28:44,932 --> 00:28:47,684 There is a niche in the Oracle Room, 491 00:28:47,768 --> 00:28:49,728 that if you spoke into it, it could resonate 492 00:28:49,811 --> 00:28:51,980 throughout the whole structure. 493 00:28:52,022 --> 00:28:55,025 And so, some thought it was significant, 494 00:28:55,108 --> 00:28:58,070 that a priest might've intoned into it a voice‐‐ 495 00:28:58,153 --> 00:29:01,281 that his booming voice would go through the whole Hypogeum. 496 00:29:01,365 --> 00:29:03,659 Uh, like a god. 497 00:29:03,742 --> 00:29:08,538 SHATNER: The voice of a god? 498 00:29:08,622 --> 00:29:11,959 Those who have visited the Malta Hypogeum 499 00:29:12,000 --> 00:29:16,129 describe it as feeling like a descent 500 00:29:16,171 --> 00:29:18,382 into the underworld. 501 00:29:18,465 --> 00:29:20,217 As a result, some experts believe 502 00:29:20,300 --> 00:29:23,637 this subterranean nightmare was intentionally constructed 503 00:29:23,720 --> 00:29:29,268 to enable its visitors to speak with the dead. 504 00:29:29,351 --> 00:29:34,648 STEAVU: Overtone chanting is a common practice 505 00:29:34,731 --> 00:29:36,817 in many cultures in, uh, East Asia, 506 00:29:36,900 --> 00:29:39,444 and, uh, North Asia and South Asia as well. 507 00:29:39,528 --> 00:29:42,906 You do have this strong connection between chanting 508 00:29:42,990 --> 00:29:47,035 and communication with the divine or with the deceased. 509 00:29:47,119 --> 00:29:50,998 And I believe at the Hypogeum, we may have a similar situation 510 00:29:51,081 --> 00:29:54,126 in which there seems to have been an active ritual function 511 00:29:54,209 --> 00:29:59,172 of, uh, not only placing the deceased or remains there, 512 00:29:59,256 --> 00:30:03,260 but where people would attempt to establish communication 513 00:30:03,343 --> 00:30:05,137 with the dead. 514 00:30:07,014 --> 00:30:12,477 In the range of 110 to 112 hertz is a frequency that, uh, 515 00:30:12,561 --> 00:30:14,521 has a specific effect on our brain. 516 00:30:14,604 --> 00:30:18,900 It puts us in a sleep state and has us producing alpha waves. 517 00:30:18,984 --> 00:30:21,945 What happens when the alpha waves are produced 518 00:30:22,029 --> 00:30:25,824 is that it kind of quiets the, um, language center of our brain 519 00:30:25,866 --> 00:30:29,911 and puts us in more of a meditative or trance‐like state. 520 00:30:29,995 --> 00:30:33,832 It's similar, in many regards, to what happens, uh, 521 00:30:33,874 --> 00:30:37,419 when a shaman uses the practice of ingesting 522 00:30:37,502 --> 00:30:40,630 psychoactive chemicals, whether it's ayahuasca 523 00:30:40,672 --> 00:30:44,092 or whether it's, uh, mushrooms of some type. 524 00:30:44,176 --> 00:30:46,303 STEAVU: So, it stands to reason that, potentially, 525 00:30:46,386 --> 00:30:50,974 people could attain a different level of consciousness 526 00:30:51,016 --> 00:30:54,978 in which they would be susceptible to have experiences 527 00:30:55,020 --> 00:30:58,899 of communicating with the dead or with the divine. 528 00:31:01,068 --> 00:31:02,694 SHATNER: As far‐fetched as the notion 529 00:31:02,778 --> 00:31:05,280 of communicating with the dead may seem to us, 530 00:31:05,364 --> 00:31:08,492 some believe whoever built the Hypogeum 531 00:31:08,533 --> 00:31:10,160 may have been on to something. 532 00:31:10,243 --> 00:31:14,581 Because it appears they left behind instructions. 533 00:31:16,708 --> 00:31:19,961 DEVEREUX: There is this spiralic painting 534 00:31:20,003 --> 00:31:23,423 on the ceiling of the, uh, Oracle Room. 535 00:31:23,507 --> 00:31:28,136 And it's not unusual to use spiralic shapes in prehistory 536 00:31:28,178 --> 00:31:33,809 and early times to represent‐‐ visually, graphically‐‐ 537 00:31:33,892 --> 00:31:36,812 represent sound in terms of spirals. 538 00:31:36,895 --> 00:31:39,439 So it was clearly an intellectual connection. 539 00:31:39,523 --> 00:31:43,318 KREISBERG: The clues may lie right before our eyes. 540 00:31:43,402 --> 00:31:46,905 Those sounds, those songs, those tones, those frequencies 541 00:31:46,988 --> 00:31:49,366 that were played and heard 542 00:31:49,449 --> 00:31:51,910 were of the utmost importance to them. 543 00:31:51,993 --> 00:31:54,121 We don't understand exactly why. 544 00:31:54,204 --> 00:31:58,875 But by studying them, hopefully, we can shed some light 545 00:31:58,959 --> 00:32:01,086 on not only what they were trying to do 546 00:32:01,169 --> 00:32:03,797 but how we could use those same concepts, 547 00:32:03,839 --> 00:32:05,715 those same understandings, 548 00:32:05,799 --> 00:32:09,177 to perhaps benefit our society today. 549 00:32:09,886 --> 00:32:14,474 An ancient necropolis 550 00:32:14,558 --> 00:32:16,643 constructed and designed 551 00:32:16,726 --> 00:32:18,645 to allow people to send messages 552 00:32:18,687 --> 00:32:20,897 into the afterlife? 553 00:32:20,981 --> 00:32:22,816 Fascinating... 554 00:32:22,899 --> 00:32:26,653 albeit a disturbing concept. 555 00:32:26,736 --> 00:32:29,990 Not unlike one of the most persistent and bizarre theories 556 00:32:30,031 --> 00:32:31,825 about our planet. 557 00:32:31,908 --> 00:32:35,162 The notion that it could be... 558 00:32:35,245 --> 00:32:37,581 hollow. 559 00:32:46,298 --> 00:32:49,801 SHATNER: Acclaimed novelist whJules Verne publishest. 560 00:32:49,843 --> 00:32:51,344 the science‐fiction novel 561 00:32:51,428 --> 00:32:54,139 A Journey to the Center of the Earth. 562 00:32:54,181 --> 00:32:57,017 The book‐‐ which chronicles an adventure 563 00:32:57,100 --> 00:32:59,811 through a fantastical subterranean world 564 00:32:59,853 --> 00:33:01,980 filled with mammoth creatures, 565 00:33:02,063 --> 00:33:03,482 underground oceans, 566 00:33:03,565 --> 00:33:08,320 and crystal caves‐‐ is an instant success. 567 00:33:08,361 --> 00:33:12,699 But despite Jules Verne's insistence that the story 568 00:33:12,782 --> 00:33:14,659 is nothing more than a work of fantasy, 569 00:33:14,701 --> 00:33:16,995 many wondered... 570 00:33:17,037 --> 00:33:19,789 could some of what he wrote 571 00:33:19,873 --> 00:33:22,501 actually be true? 572 00:33:22,542 --> 00:33:26,963 We live on the surface of planet Earth, 573 00:33:27,047 --> 00:33:31,885 but going back many thousands of years, 574 00:33:31,968 --> 00:33:35,555 we have wondered what is beneath our feet. 575 00:33:35,639 --> 00:33:37,766 Is it solid? 576 00:33:37,849 --> 00:33:40,852 Or is it possible that it could be hollow? 577 00:33:40,936 --> 00:33:43,939 BRANDENBURG: One of the most fascinating people 578 00:33:44,022 --> 00:33:46,650 in the history of science is Edmond Halley, 579 00:33:46,733 --> 00:33:49,277 who Halley's Comet is named after. 580 00:33:49,361 --> 00:33:52,656 Based on his explorations, 581 00:33:52,697 --> 00:33:55,909 he discovered the Earth's magnetic field was fluctuating, 582 00:33:55,992 --> 00:34:00,455 that it was not a steady, uniform object. 583 00:34:01,706 --> 00:34:03,375 It was changing in time. 584 00:34:03,458 --> 00:34:05,210 It appeared to be kind of rotating 585 00:34:05,293 --> 00:34:07,462 relative to the surface of the Earth. 586 00:34:07,504 --> 00:34:10,966 So he came up with a quite elaborate model 587 00:34:11,007 --> 00:34:13,385 to try to explain what he was seeing 588 00:34:13,468 --> 00:34:15,929 in his measurements of the Earth's magnetic field. 589 00:34:16,012 --> 00:34:19,224 And one of the interesting theories he came up with 590 00:34:19,307 --> 00:34:21,977 was the idea of a hollow Earth. 591 00:34:22,018 --> 00:34:24,563 REDFERN: Edmond Halley 592 00:34:24,646 --> 00:34:27,524 believed there were essentially three crusts‐‐ 593 00:34:27,607 --> 00:34:31,778 three rotating crusts which surrounded this huge, 594 00:34:31,861 --> 00:34:35,615 hollowed‐out portion of planet Earth. 595 00:34:35,699 --> 00:34:38,034 SHATNER: A hollow Earth? 596 00:34:38,118 --> 00:34:41,454 Is it possible that there's actually another world 597 00:34:41,538 --> 00:34:44,958 located deep within the Earth's crust? 598 00:34:45,041 --> 00:34:49,170 Could Jules Verne's fantastical notion of a subterranean world 599 00:34:49,254 --> 00:34:52,591 located deep underground have been based 600 00:34:52,674 --> 00:34:55,093 not on mere imagination 601 00:34:55,176 --> 00:34:57,971 but on scientific fact? 602 00:34:58,054 --> 00:35:03,435 Well, if one legendary explorer is to be believed, 603 00:35:03,518 --> 00:35:05,270 the answer is yes. 604 00:35:05,353 --> 00:35:10,817 And he claimed to have even seen it firsthand. 605 00:35:10,859 --> 00:35:13,945 REDFERN: Rear Admiral Richard Byrd, 606 00:35:14,029 --> 00:35:17,365 in essence, was somebody who we could equate 607 00:35:17,449 --> 00:35:21,286 with, like, a real‐life Indiana Jones. 608 00:35:21,369 --> 00:35:22,829 He traveled around the world 609 00:35:22,912 --> 00:35:25,123 having expeditions and adventures. 610 00:35:25,206 --> 00:35:28,960 He was someone who visited 611 00:35:29,044 --> 00:35:32,881 the polar areas, which really fascinated him. 612 00:35:32,964 --> 00:35:35,842 And in 1926, 613 00:35:35,925 --> 00:35:38,345 while flying over the caps, 614 00:35:38,428 --> 00:35:40,722 he was able to see what he described 615 00:35:40,805 --> 00:35:44,809 as like a large green valley. 616 00:35:44,893 --> 00:35:48,396 NEWMAN: One of the ideas about this whole hollow Earth theory 617 00:35:48,480 --> 00:35:52,150 is that there were multiple entrances all over the world. 618 00:35:52,192 --> 00:35:55,028 But most notably, the North and South Poles 619 00:35:55,111 --> 00:35:57,405 are possibly the entrance for these. 620 00:35:57,489 --> 00:36:00,200 REDFERN: According to the story, 621 00:36:00,283 --> 00:36:03,453 Byrd described massive forest areas 622 00:36:03,536 --> 00:36:07,916 nurtured by some kind of sun 623 00:36:07,999 --> 00:36:10,335 deep inside the planet itself. 624 00:36:10,418 --> 00:36:13,296 And he claimed to have seen, uh, 625 00:36:13,380 --> 00:36:15,507 a fully grown woolly mammoth, 626 00:36:15,590 --> 00:36:20,136 which it would be amazing if that was true. 627 00:36:20,178 --> 00:36:22,597 SHATNER: Underground rivers, 628 00:36:22,681 --> 00:36:27,310 extinct mammoths and a sun deep inside the Earth? 629 00:36:27,394 --> 00:36:30,939 Could the incredible account of Admiral Byrd‐‐ 630 00:36:31,022 --> 00:36:33,650 one of the world's greatest explorers‐‐ 631 00:36:33,733 --> 00:36:35,568 actually be true? 632 00:36:35,652 --> 00:36:37,112 But if so, 633 00:36:37,195 --> 00:36:39,864 where's the evidence? 634 00:36:42,450 --> 00:36:45,412 There's water on the surface in huge oceans. 635 00:36:45,495 --> 00:36:47,455 What if there's a hole in the mantle 636 00:36:47,539 --> 00:36:49,290 that allows some of it to drain somewhere? 637 00:36:49,374 --> 00:36:50,667 Did it get captured there 638 00:36:50,750 --> 00:36:53,128 when the Earth was created in its formation? 639 00:36:53,211 --> 00:36:55,130 I'll give you an example. 640 00:36:55,171 --> 00:36:57,298 In Mammoth Cave in Kentucky, 641 00:36:57,382 --> 00:36:59,467 there were the remains of a shark 642 00:36:59,551 --> 00:37:02,470 from 330 million years ago. 643 00:37:02,512 --> 00:37:05,974 An extinct creature found in this cave, 644 00:37:06,057 --> 00:37:08,309 in a cave‐‐ not in an ocean but in a cave. 645 00:37:08,393 --> 00:37:12,021 What if this cave was part of an ocean system 646 00:37:12,105 --> 00:37:14,399 that went deeper underground? 647 00:37:14,482 --> 00:37:17,026 BRANDENBURG: As a scientist, 648 00:37:17,110 --> 00:37:18,903 the first thing I will concede, 649 00:37:18,987 --> 00:37:22,615 is that we do know there are vast caverns below us, 650 00:37:22,699 --> 00:37:25,201 and there are vast structures that are dynamic 651 00:37:25,285 --> 00:37:26,995 under the Earth. 652 00:37:27,078 --> 00:37:29,956 And so it's certainly possible. 653 00:37:30,039 --> 00:37:34,794 The Earth is about 7,000 to 8,000 miles in diameter. 654 00:37:34,878 --> 00:37:36,880 That's pretty big. 655 00:37:36,963 --> 00:37:40,467 We've only ever drilled to about eight miles deep. 656 00:37:40,508 --> 00:37:43,553 We have no idea what's at the center of the Earth. 657 00:37:43,636 --> 00:37:46,931 You know, we have theories that there's this molten ball core, 658 00:37:47,015 --> 00:37:49,100 iron core spinning around, it's magnetized or whatever, 659 00:37:49,184 --> 00:37:51,144 but we really don't know. 660 00:37:51,227 --> 00:37:53,563 There could be a completely different world 661 00:37:53,646 --> 00:37:55,398 that we just don't understand yet 662 00:37:55,482 --> 00:37:57,317 because we've never been there 663 00:37:57,400 --> 00:37:59,068 to do experiments and science on it 664 00:37:59,152 --> 00:38:00,779 and understand what's going on. 665 00:38:00,862 --> 00:38:04,824 SHATNER: If another world does exist deep beneath our own, 666 00:38:04,908 --> 00:38:09,370 is it possible we might be able to one day access it? 667 00:38:09,454 --> 00:38:13,708 There are those who believe that not only is the answer yes, 668 00:38:13,792 --> 00:38:17,045 but that humanity's very future may lie 669 00:38:17,128 --> 00:38:20,507 not above ground but down below. 670 00:38:20,590 --> 00:38:25,428 As proof, they point to a village in China 671 00:38:25,512 --> 00:38:27,055 where thousands of people 672 00:38:27,138 --> 00:38:30,517 are already living deep underground. 673 00:38:41,694 --> 00:38:44,489 in the rural region of Sanmenxia 674 00:38:44,572 --> 00:38:47,116 lies an ancient network of villages 675 00:38:47,200 --> 00:38:49,452 that exists entirely underground. 676 00:38:49,536 --> 00:38:52,497 Millions of people have lived and worked here 677 00:38:52,539 --> 00:38:54,207 spending their entire lives 678 00:38:54,290 --> 00:38:56,501 beneath the surface for generations. 679 00:38:56,584 --> 00:38:58,962 And not just thousands of years ago, 680 00:38:59,045 --> 00:39:00,839 in the ancient past... 681 00:39:00,922 --> 00:39:03,299 but to this very day. 682 00:39:03,383 --> 00:39:08,888 COLLINS: Over the past 4,000 years 683 00:39:08,972 --> 00:39:11,307 there were tens, 684 00:39:11,391 --> 00:39:14,227 if not hundreds of thousands of people 685 00:39:14,310 --> 00:39:16,646 living within these underground 686 00:39:16,688 --> 00:39:19,816 dwellings in the northern part of China. 687 00:39:19,858 --> 00:39:23,736 And these places, which are known generally 688 00:39:23,820 --> 00:39:25,238 as yaodongs, 689 00:39:25,321 --> 00:39:29,033 continue to be built even to this day, 690 00:39:29,117 --> 00:39:31,494 and, in fact, the modern examples 691 00:39:31,578 --> 00:39:33,746 created over the last hundred years 692 00:39:33,830 --> 00:39:38,877 have got bathrooms, they've got electricity. 693 00:39:38,960 --> 00:39:40,753 If you could imagine a sort of 694 00:39:40,837 --> 00:39:44,173 modern‐day housing development anywhere in the world, 695 00:39:44,257 --> 00:39:49,012 everybody had a basement and you took all of the houses away, 696 00:39:49,095 --> 00:39:52,181 and all you were left with was the basements... 697 00:39:52,265 --> 00:39:54,392 that's what Sanmenxia looks like. 698 00:39:54,475 --> 00:39:57,186 It's these sort of rectangular 699 00:39:57,270 --> 00:39:59,522 holes in the ground, like a chessboard, 700 00:39:59,606 --> 00:40:01,649 all over the place. 701 00:40:01,691 --> 00:40:04,569 SHATNER: There are many living options 702 00:40:04,652 --> 00:40:07,196 in the underground dwellings of Sanmenxia, 703 00:40:07,280 --> 00:40:10,366 ranging from simple one‐bedroom caves... 704 00:40:10,450 --> 00:40:13,161 to more elaborate three‐bedroom homes 705 00:40:13,202 --> 00:40:15,538 with modern appliances and plumbing. 706 00:40:15,622 --> 00:40:19,876 But why would anyone choose to live below ground 707 00:40:19,959 --> 00:40:24,297 in a country with several thriving cities to choose from? 708 00:40:24,380 --> 00:40:26,466 One of the benefits of living underground, 709 00:40:26,507 --> 00:40:29,469 especially in very hot and cold climates, 710 00:40:29,552 --> 00:40:32,639 is below the earth, the temperature is more moderated, 711 00:40:32,680 --> 00:40:34,807 so you don't get the extremes so much. 712 00:40:34,849 --> 00:40:36,434 You know, it's probably pretty cool 713 00:40:36,517 --> 00:40:38,186 most of the time and so, 714 00:40:38,269 --> 00:40:40,772 you know, they're not bad places to be. 715 00:40:40,855 --> 00:40:44,275 COLLINS: It could well be that with the expansion 716 00:40:44,359 --> 00:40:48,529 of population at the rate that it is today 717 00:40:48,613 --> 00:40:50,823 that going underground 718 00:40:50,865 --> 00:40:55,662 is something that we should look towards in the future 719 00:40:55,703 --> 00:40:59,540 to solving the problems of housing 720 00:41:00,416 --> 00:41:03,461 and creating new cities. 721 00:41:04,963 --> 00:41:08,049 You have to wonder, is the day gonna come 722 00:41:08,132 --> 00:41:09,634 when the Earth itself, 723 00:41:09,717 --> 00:41:12,136 at least from the perspective of the surface, 724 00:41:12,178 --> 00:41:14,180 that the Earth simply will not 725 00:41:14,263 --> 00:41:17,016 be able to stand any more people. 726 00:41:17,100 --> 00:41:19,519 So what's the answer? 727 00:41:19,602 --> 00:41:23,523 Maybe the answer is that we all move underground 728 00:41:23,606 --> 00:41:27,819 or possibly a significant percentage 729 00:41:27,902 --> 00:41:32,156 of the population choose to go underground. 730 00:41:32,198 --> 00:41:35,702 Given everything going on in the world today, 731 00:41:35,785 --> 00:41:37,996 will we live to see the day when our civilization 732 00:41:38,079 --> 00:41:40,331 goes back underground? 733 00:41:40,373 --> 00:41:42,417 It certainly seems safer. 734 00:41:42,500 --> 00:41:44,544 And if that comes to pass, 735 00:41:44,627 --> 00:41:47,672 will we then learn about all the other secrets 736 00:41:47,755 --> 00:41:51,467 the Earth is hiding beneath its surface? 737 00:41:51,551 --> 00:41:54,637 It seems that the answer will be one 738 00:41:54,721 --> 00:41:57,974 that for now remains buried, 739 00:41:58,016 --> 00:41:59,976 and... unexplained. 740 00:42:00,018 --> 00:42:06,272 CAPTIONING PROVIDED BY A+E NETWORKS