1 00:00:14,040 --> 00:00:17,760 [Graham] What I'm suggesting is that something that we would recognize 2 00:00:17,840 --> 00:00:22,120 as an advanced civilization existed during the Ice Age. 3 00:00:22,960 --> 00:00:25,640 I'm not saying that they flew to the moon. 4 00:00:29,840 --> 00:00:33,920 But what I'm saying is that they were far, far, far more advanced 5 00:00:34,000 --> 00:00:35,800 in terms of scientific knowledge. 6 00:00:38,080 --> 00:00:40,920 Knowledge of the Earth, knowledge of the universe, 7 00:00:41,000 --> 00:00:42,560 than we're taught. 8 00:00:44,800 --> 00:00:48,040 And capable of astounding feats of engineering, 9 00:00:49,320 --> 00:00:52,720 like the site I'm heading to in Turkey's Cappadocia region. 10 00:00:54,400 --> 00:00:58,440 There's an ancient survival bunker deep underground… 11 00:01:02,040 --> 00:01:06,440 built not just to shelter a few people, but to shelter thousands. 12 00:01:08,200 --> 00:01:11,840 Mainstream historians have long debated its purpose, 13 00:01:11,920 --> 00:01:14,480 but I believe it might just explain 14 00:01:14,560 --> 00:01:19,800 how this lost ancient civilization I've been looking for became lost. 15 00:01:21,120 --> 00:01:24,160 This is the story of Derinkuyu. 16 00:01:42,680 --> 00:01:46,960 I've come to a region of Turkey known as Cappadocia. 17 00:01:49,560 --> 00:01:55,880 About 240 miles northwest of those mysterious enclosures of Göbekli Tepe… 18 00:01:57,320 --> 00:01:59,480 that were intentionally buried, 19 00:02:01,040 --> 00:02:05,720 memorializing a time of great cataclysms at the end of the Ice Age. 20 00:02:09,440 --> 00:02:13,600 Millions of years ago, this region's landscape was transformed 21 00:02:13,680 --> 00:02:20,320 by a series of volcanic eruptions, leaving layer upon layer of ash, 22 00:02:20,400 --> 00:02:25,160 which compressed over millennia into a soft stone called tuff. 23 00:02:26,920 --> 00:02:29,720 A stone easily shaped by the elements, 24 00:02:29,800 --> 00:02:32,760 creating what locals call "fairy chimneys." 25 00:02:33,880 --> 00:02:37,200 But a stone that also allowed the construction 26 00:02:37,280 --> 00:02:41,040 of one of the most remarkable large-scale projects 27 00:02:41,120 --> 00:02:46,160 humanity has ever embarked upon deep beneath this soft rock. 28 00:02:47,240 --> 00:02:49,360 Just a few miles from where I stand, 29 00:02:49,440 --> 00:02:54,440 the mysterious hidden city created thousands of years ago has been revealed. 30 00:02:54,520 --> 00:02:57,840 It's the work of an as-yet unidentified civilization 31 00:02:57,920 --> 00:03:00,520 that was clearly motivated by fear. 32 00:03:00,600 --> 00:03:03,760 The big question therefore is, fear of what? 33 00:03:14,520 --> 00:03:18,160 The closest town, Derinkuyu, seems unremarkable. 34 00:03:20,800 --> 00:03:26,320 But in 1963, developers renovating a house here knocked through a floor, 35 00:03:27,920 --> 00:03:33,880 only to discover a deep tunnel, one that led to a forgotten world. 36 00:03:35,360 --> 00:03:39,360 It's hard to believe, as you walk the dusty streets of this small town, 37 00:03:39,840 --> 00:03:43,240 that carved out of the living bedrock right beneath my feet 38 00:03:43,840 --> 00:03:47,600 is an ancient, immense and mysterious subterranean complex. 39 00:03:50,840 --> 00:03:54,200 If you're claustrophobic, consider yourself warned. 40 00:03:56,960 --> 00:03:58,720 We're headed underground. 41 00:04:06,040 --> 00:04:09,080 This is the underground city of Derinkuyu. 42 00:04:12,720 --> 00:04:15,560 A series of stone tunnels and chambers 43 00:04:15,640 --> 00:04:19,040 plunging as deep as 85 meters below the surface… 44 00:04:21,279 --> 00:04:24,040 creating 18 levels of rooms and tunnels. 45 00:04:26,839 --> 00:04:31,320 The entire complex was hacked out of the rock with hand axes. 46 00:04:32,680 --> 00:04:34,840 A disorientating warren 47 00:04:34,920 --> 00:04:37,960 that occasionally widens into large open spaces. 48 00:04:39,080 --> 00:04:44,200 From inside, it's virtually impossible to get a sense of the scale of the place. 49 00:04:45,680 --> 00:04:48,440 But most of this underground city has been mapped, 50 00:04:50,000 --> 00:04:52,920 and if we take away the rock between the spaces, 51 00:04:53,720 --> 00:04:55,840 we can see a cross section of the city, 52 00:04:57,200 --> 00:04:59,000 and it's utterly astounding. 53 00:05:02,600 --> 00:05:09,120 It's an ant farm built human size, with subterranean caves and tunnels 54 00:05:09,200 --> 00:05:12,680 extending over an area of four square kilometers. 55 00:05:14,160 --> 00:05:20,000 To keep it well-ventilated, Derinkuyu has upwards of 15,000 air ducts 56 00:05:20,080 --> 00:05:22,360 connecting the upper levels to the surface… 57 00:05:25,200 --> 00:05:27,760 and more than 50 vertical shafts, 58 00:05:27,840 --> 00:05:32,720 some stretching all the way down to the water table 85 meters below the surface… 59 00:05:36,280 --> 00:05:38,320 giving the complex its name. 60 00:05:38,400 --> 00:05:41,120 Derinkuyu means, "deep well." 61 00:05:45,040 --> 00:05:48,480 Stunning in its ingenuity and architectural complexity, 62 00:05:48,560 --> 00:05:53,640 it's calculated that Derinkuyu could shelter up to 20,000 people. 63 00:05:54,320 --> 00:05:55,560 But questions remain. 64 00:05:56,240 --> 00:05:59,520 Which people, when and why? 65 00:06:02,600 --> 00:06:04,360 It's hard to know precisely, 66 00:06:05,080 --> 00:06:09,840 because Derinkuyu is like a crime scene that's been trampled on for generations. 67 00:06:13,280 --> 00:06:16,040 Many cultures have passed through this part of Turkey. 68 00:06:17,000 --> 00:06:21,240 For centuries, Cappadocia occupied a place of strategic importance, 69 00:06:22,400 --> 00:06:26,920 along the legendary Silk Road that connected Asia to Europe, 70 00:06:27,560 --> 00:06:29,880 going back to the time of Alexander the Great. 71 00:06:32,280 --> 00:06:34,480 Turkish scholar, Sevim Tunçdemir, 72 00:06:34,560 --> 00:06:38,440 is an expert on the Derinkuyu tunnels and their various occupants. 73 00:06:38,960 --> 00:06:41,640 [in Turkish] This region has been home to many civilizations. 74 00:06:41,720 --> 00:06:45,080 If we count them starting from the beginning, 75 00:06:45,760 --> 00:06:47,440 there were the Hittites, 76 00:06:47,520 --> 00:06:50,080 then there were the Phrygians, then the Persians, 77 00:06:50,920 --> 00:06:52,600 the Cappadocian kingdom, 78 00:06:52,680 --> 00:06:54,080 the Roman Empire. 79 00:06:54,160 --> 00:06:56,960 All the people who passed through used them. 80 00:06:57,520 --> 00:07:02,320 They were even in use up until the Ottoman period. 81 00:07:04,800 --> 00:07:06,760 [Graham] When the tunnels were first discovered, 82 00:07:06,840 --> 00:07:10,440 archaeologists found artifacts left by early Christians, 83 00:07:12,000 --> 00:07:15,200 and in the deepest levels, secret meeting rooms 84 00:07:15,280 --> 00:07:18,200 carved out with vaulted ceilings like churches. 85 00:07:19,800 --> 00:07:21,360 So the original theory, 86 00:07:21,440 --> 00:07:24,080 which many historians still cling to today, 87 00:07:24,680 --> 00:07:26,680 was that the tunnels beneath Derinkuyu 88 00:07:26,760 --> 00:07:30,200 were carved out by Christians in the 7th century AD, 89 00:07:32,200 --> 00:07:34,920 trying to hide from Arab raiding parties. 90 00:07:36,440 --> 00:07:38,920 It's a tale that appeals to Western tourists. 91 00:07:39,880 --> 00:07:42,200 Also, it's totally wrong. 92 00:07:45,160 --> 00:07:49,280 Later excavations found evidence of people using this underground city 93 00:07:49,360 --> 00:07:52,000 as early as the 8th century BC, 94 00:07:52,600 --> 00:07:55,720 hundreds of years before the Christians were here. 95 00:07:57,840 --> 00:08:01,760 We encounter this again and again on archaeological sites around the world. 96 00:08:01,840 --> 00:08:06,240 There's a big notice based on the received wisdom of archaeologists, 97 00:08:06,320 --> 00:08:09,000 and again and again that notice is wrong. 98 00:08:09,760 --> 00:08:11,040 Factually wrong. 99 00:08:11,120 --> 00:08:14,640 Proved to be wrong by later excavations and yet not changed. 100 00:08:15,200 --> 00:08:18,600 Don't trust the noticeboards. Do the legwork yourself. 101 00:08:18,680 --> 00:08:21,200 Don't rely on the so-called experts. 102 00:08:25,080 --> 00:08:28,400 There were many cultures who used these tunnels over centuries, 103 00:08:29,480 --> 00:08:33,280 but what I want to know is who began this remarkable project. 104 00:08:34,440 --> 00:08:36,360 How far back does it go? 105 00:08:38,400 --> 00:08:43,679 Historian Hüsam Süleymangil has been investigating this site for decades, 106 00:08:43,760 --> 00:08:46,400 trying to unlock its mysterious origins. 107 00:08:47,720 --> 00:08:53,720 So, when I look at Derinkuyu and the complexity of it, I am mystified. 108 00:08:53,800 --> 00:08:57,680 When do you think that this project started? 109 00:08:57,760 --> 00:08:59,840 There are several different theories about it 110 00:08:59,920 --> 00:09:02,760 and none of them is really proven by science. 111 00:09:02,840 --> 00:09:03,680 Right. 112 00:09:03,760 --> 00:09:05,800 They couldn't find any written information. 113 00:09:05,880 --> 00:09:09,920 They couldn't find any organic material to use to carbon date. 114 00:09:10,000 --> 00:09:11,480 Are there any carbon dates at all? 115 00:09:11,560 --> 00:09:13,760 As far as I know, there is no carbon dating. 116 00:09:13,840 --> 00:09:14,680 That's extraordinary. 117 00:09:14,760 --> 00:09:17,240 So, the date is still a big mystery. 118 00:09:21,400 --> 00:09:23,400 I have my own theories, 119 00:09:23,480 --> 00:09:25,160 but Hüsam proposes a date 120 00:09:25,240 --> 00:09:29,000 based on the oldest known culture to use these caves. 121 00:09:29,800 --> 00:09:32,040 Most plausible theory, according to my mind, 122 00:09:32,120 --> 00:09:35,360 is actually about the 8th century BC. 123 00:09:37,200 --> 00:09:39,160 [Graham] At that time, this part of the world 124 00:09:39,240 --> 00:09:42,280 was inhabited by a people known as the Phrygians, 125 00:09:43,400 --> 00:09:47,040 who were under threat from another empire, the Assyrians. 126 00:09:49,000 --> 00:09:52,960 We know that there was a big Assyrian army coming from southeast. 127 00:09:55,240 --> 00:09:59,120 [Graham] The Phrygians would've viewed the invading army with sheer terror. 128 00:10:02,160 --> 00:10:05,240 The Assyrians were notorious for skinning prisoners, 129 00:10:05,800 --> 00:10:09,640 impaling them and burning children alive. 130 00:10:12,800 --> 00:10:14,320 According to later accounts, 131 00:10:14,400 --> 00:10:18,000 when the Assyrian invaders marched against the people in this valley, 132 00:10:18,640 --> 00:10:22,280 they were surprised by the defenders' innovative tactics. 133 00:10:27,920 --> 00:10:31,240 [Hüsam] The Phrygians were fighting against the Assyrian army 134 00:10:31,320 --> 00:10:32,840 in the guerilla type of warfare, 135 00:10:32,920 --> 00:10:35,440 attacking the army in sort of unexpected places. 136 00:10:35,520 --> 00:10:37,000 When the army start to chase them, 137 00:10:37,080 --> 00:10:39,680 they would come and use these as hideout places. 138 00:10:42,600 --> 00:10:45,520 [Graham] It's a time-honored strategy in guerrilla warfare. 139 00:10:47,840 --> 00:10:51,320 Similar tunnels were dug out by the Viet Cong in South Vietnam. 140 00:10:52,680 --> 00:10:54,880 And Afghan rebels did the same 141 00:10:55,400 --> 00:10:59,200 to hide from superior Soviet and then American invading forces. 142 00:11:01,920 --> 00:11:03,480 This official position, 143 00:11:03,560 --> 00:11:07,400 that the Phrygians dug out these tunnels as a secret military base, 144 00:11:08,080 --> 00:11:11,920 seems to be supported by one of the complex's more clever features… 145 00:11:14,080 --> 00:11:17,520 massive stone discs that can be rolled into place, 146 00:11:17,600 --> 00:11:19,120 sealing up the passageways. 147 00:11:22,160 --> 00:11:25,960 These rolling doors have a diameter of up to five feet 148 00:11:26,640 --> 00:11:28,200 and can weigh up to half a ton. 149 00:11:32,480 --> 00:11:35,560 On the inside surface, the disc has a hole. 150 00:11:36,520 --> 00:11:41,400 Insert a smaller locking stone as a handle and you can roll the door shut, 151 00:11:42,360 --> 00:11:46,040 creating a smooth, formidable barrier for anyone on the other side. 152 00:11:54,560 --> 00:11:58,360 But did the Phrygians really make these ingenious doors, 153 00:11:59,640 --> 00:12:01,560 or were they already here? 154 00:12:03,520 --> 00:12:05,880 They're carved from the same compressed ash 155 00:12:05,960 --> 00:12:07,640 that made the fairy chimneys. 156 00:12:11,600 --> 00:12:16,720 The same soft rock that allowed someone to dig all this out in the first place. 157 00:12:18,880 --> 00:12:22,720 They're certainly sealable doors, separating the levels from each other, 158 00:12:22,800 --> 00:12:26,360 requiring sophisticated engineering to fit in place. 159 00:12:26,440 --> 00:12:28,080 But the stone is soft 160 00:12:28,160 --> 00:12:31,160 and determined attackers armed with sledgehammers and chisels 161 00:12:31,240 --> 00:12:33,120 could easily have broken through, 162 00:12:33,200 --> 00:12:37,400 rendering all the effort to make these megaliths completely useless. 163 00:12:37,480 --> 00:12:41,480 I'm beginning to wonder if they were designed to deter human attackers at all. 164 00:12:44,240 --> 00:12:48,080 To me, these look less like defensive fortifications 165 00:12:48,160 --> 00:12:51,600 and more like a clever way to allow privacy between sections, 166 00:12:53,200 --> 00:12:55,200 or to prevent fires from spreading. 167 00:12:57,560 --> 00:13:02,080 Even if this place was originally built as a military installation, 168 00:13:02,160 --> 00:13:04,000 why dig it out here? 169 00:13:06,000 --> 00:13:07,840 There was nothing here to defend. 170 00:13:09,640 --> 00:13:11,560 [Sevim, in Turkish] There were no settlements 171 00:13:12,240 --> 00:13:16,680 above ground in Derinkuyu until 1830. 172 00:13:21,520 --> 00:13:26,080 The notion that these are places where people went to hide from invading armies 173 00:13:26,160 --> 00:13:27,840 makes very little sense to me. 174 00:13:27,920 --> 00:13:30,560 When an invading army comes into a territory, 175 00:13:30,640 --> 00:13:33,400 they come to take, possess and occupy that territory. 176 00:13:33,480 --> 00:13:37,280 All they have to do is block the entrances and wait till you die of starvation. 177 00:13:38,160 --> 00:13:41,160 So that idea just doesn't make any sense at all. 178 00:13:42,280 --> 00:13:45,520 See, in my opinion, I think scholarship is going too far 179 00:13:45,600 --> 00:13:47,560 to say this was the 8th century BC 180 00:13:47,640 --> 00:13:50,800 because those are the earliest dates that we find people using it. 181 00:13:50,880 --> 00:13:51,840 Right. 182 00:13:51,920 --> 00:13:54,800 But that we don't necessarily know that they made it then. 183 00:13:54,880 --> 00:13:56,800 Maybe it was already made. 184 00:13:56,880 --> 00:13:58,680 Quite possible, as it's still a mystery. 185 00:13:58,760 --> 00:14:00,760 -It's just the most plausible theory… -Yes. 186 00:14:00,840 --> 00:14:02,680 …not the only correct theory. 187 00:14:07,600 --> 00:14:09,520 [Graham] The dating of this underground city 188 00:14:09,600 --> 00:14:13,480 is about as insecure as it's possible for archaeological dating to be. 189 00:14:15,320 --> 00:14:19,480 All the proposed dates derive from use of the structure at different periods. 190 00:14:19,560 --> 00:14:21,720 The fact that I live in a house today 191 00:14:21,800 --> 00:14:24,120 doesn't mean it was built immediately before I moved in. 192 00:14:32,320 --> 00:14:36,520 It's a notion that leads me to question the official dating of these tunnels. 193 00:14:37,680 --> 00:14:39,120 Could they be older, 194 00:14:39,920 --> 00:14:43,320 much older, than the accepted theory says? 195 00:14:45,320 --> 00:14:50,400 And was the reason for their construction not to hide from an invading army 196 00:14:51,920 --> 00:14:53,920 but to hide from something else? 197 00:14:56,280 --> 00:15:00,320 In the most ancient levels, the ones closest to the surface, 198 00:15:00,400 --> 00:15:03,240 the chambers seem not to be designed for defense 199 00:15:03,320 --> 00:15:04,600 but for everyday living. 200 00:15:08,240 --> 00:15:14,320 [in Turkish] The underground cities were organized to cater for human living. 201 00:15:14,400 --> 00:15:17,800 In other words, for daily life. 202 00:15:19,040 --> 00:15:21,640 And for this, all the resources were available. 203 00:15:23,160 --> 00:15:28,040 Starting with the kitchen, to the pantry, to the living spaces. 204 00:15:30,640 --> 00:15:34,000 [in English] There are sections we know that they would use as cooking 205 00:15:34,080 --> 00:15:36,640 and we know that they created small chimneys. 206 00:15:36,720 --> 00:15:37,680 Mmm-hmm. 207 00:15:37,760 --> 00:15:41,200 At the entrance floors, there are some rooms that's named as stables. 208 00:15:41,840 --> 00:15:45,520 Animals would be the most valuable belongings of those people. 209 00:15:48,600 --> 00:15:51,720 [Graham] One area has even been identified as an ancient winery 210 00:15:52,320 --> 00:15:53,760 where grapes were crushed. 211 00:15:55,840 --> 00:15:58,680 Indeed, the tunnels would make a great wine cellar. 212 00:15:59,600 --> 00:16:01,480 The temperature stays quite comfortable, 213 00:16:01,560 --> 00:16:04,840 no matter how hot or cold it gets on the surface. 214 00:16:06,160 --> 00:16:08,560 Food would've stayed fresh longer down here. 215 00:16:10,920 --> 00:16:16,680 It's clear that Derinkuyu was created to be used by a substantial population. 216 00:16:17,600 --> 00:16:18,800 An underground bunker. 217 00:16:22,800 --> 00:16:24,520 Think about all the modern examples 218 00:16:24,600 --> 00:16:28,440 where humans have created vast underground living spaces. 219 00:16:29,240 --> 00:16:31,600 The Cheyenne Mountain Complex in Colorado. 220 00:16:34,080 --> 00:16:38,240 The Dixia Cheng network of tunnels dug out beneath Beijing. 221 00:16:39,800 --> 00:16:43,520 The Presidential Emergency Operations Center under the White House. 222 00:16:45,080 --> 00:16:48,600 None of these were built to defend against invading armies. 223 00:16:49,920 --> 00:16:52,120 They were built as places of refuge, 224 00:16:52,200 --> 00:16:55,800 to preserve life in the event of some kind of threat from above. 225 00:16:58,000 --> 00:17:00,800 I think that's exactly what's going on… 226 00:17:04,040 --> 00:17:05,280 at Derinkuyu. 227 00:17:07,760 --> 00:17:11,319 But I also believe this bunker was created much longer ago 228 00:17:11,400 --> 00:17:13,920 than archaeologists are willing to consider. 229 00:17:15,599 --> 00:17:17,400 There is evidence that suggests 230 00:17:17,480 --> 00:17:20,760 that Derinkuyu may go back as far as the last Ice Age. 231 00:17:25,319 --> 00:17:29,359 It concerns those telltale marks left by hand axes 232 00:17:29,440 --> 00:17:31,040 on the walls of Derinkuyu. 233 00:17:32,760 --> 00:17:35,120 Just a mile outside Derinkuyu, 234 00:17:35,200 --> 00:17:38,680 Turkish archaeologists exploring an ancient riverbed 235 00:17:38,760 --> 00:17:41,560 found several hand axes and stone tools 236 00:17:42,160 --> 00:17:46,600 dating back to around 9500 BC, 237 00:17:47,800 --> 00:17:49,400 the end of the last Ice Age. 238 00:17:50,200 --> 00:17:51,520 The same sort of tools 239 00:17:51,600 --> 00:17:55,560 that shaped Derinkuyu's shallowest and oldest chambers. 240 00:17:59,200 --> 00:18:02,920 Think about the semi-subterranean chamber at Karahan Tepe, 241 00:18:03,000 --> 00:18:05,320 less than 300 miles from here, 242 00:18:06,040 --> 00:18:08,080 with its columns that closely resemble 243 00:18:08,160 --> 00:18:11,320 the natural fairy chimney formations of Cappadocia. 244 00:18:14,160 --> 00:18:15,440 Since no one disputes 245 00:18:15,520 --> 00:18:18,800 that this chamber was carved out at the end of the last Ice Age, 246 00:18:20,760 --> 00:18:22,400 there's no reason why Derinkuyu 247 00:18:22,480 --> 00:18:24,920 couldn't have been made at around the same time. 248 00:18:29,960 --> 00:18:33,080 As Derinkuyu reveals its depth and complexity, 249 00:18:33,160 --> 00:18:37,400 what's hard to ignore is the vast scale of the enterprise 250 00:18:38,560 --> 00:18:43,040 and the enormous effort involved in tunneling it out in the first place. 251 00:18:45,600 --> 00:18:48,800 What makes this feat of engineering even more remarkable 252 00:18:49,520 --> 00:18:53,080 is that this isn't the only underground city in Cappadocia. 253 00:18:58,200 --> 00:19:01,040 In 2013, construction workers stumbled across 254 00:19:01,120 --> 00:19:03,400 another series of tunnels at Nevşehir, 255 00:19:05,360 --> 00:19:07,000 17 miles away. 256 00:19:08,040 --> 00:19:11,880 What they found was an underground city that's even larger than Derinkuyu. 257 00:19:14,800 --> 00:19:17,840 Since then, more underground cities have been discovered. 258 00:19:21,040 --> 00:19:24,120 The stunning truth is here in Cappadocia, 259 00:19:24,200 --> 00:19:28,880 archaeologists have identified 36 such underground cities. 260 00:19:32,560 --> 00:19:35,080 And if we count the ones with just two levels, 261 00:19:35,600 --> 00:19:37,760 that number balloons to 200. 262 00:19:43,200 --> 00:19:47,160 One of these underground cities, just five miles away from Derinkuyu, 263 00:19:47,240 --> 00:19:49,400 holds an incredible secret. 264 00:19:51,240 --> 00:19:54,000 The tunnels at Kaymakli run eight stories deep 265 00:19:54,080 --> 00:19:56,840 over an area wider than Derinkuyu. 266 00:19:58,920 --> 00:20:02,640 Based on the number of storage chambers carved into the walls, 267 00:20:02,720 --> 00:20:08,200 archaeologists think this bunker could've supported up to 3,500 people. 268 00:20:12,600 --> 00:20:18,320 But Kaymakli's most mind-blowing feature can be found here on the third level down. 269 00:20:22,920 --> 00:20:26,320 An underground tunnel that runs far into the distance. 270 00:20:32,200 --> 00:20:33,840 It's impassable today, 271 00:20:33,920 --> 00:20:39,000 but this blocked tunnel is claimed by some to connect Kaymakli to Derinkuyu. 272 00:20:41,280 --> 00:20:43,840 A straight-line distance of about five miles. 273 00:20:48,800 --> 00:20:51,280 In fact, archaeologists have confirmed 274 00:20:51,360 --> 00:20:55,400 that at least six other underground complexes in Cappadocia 275 00:20:55,480 --> 00:20:59,040 are connected to one another by similar underground passages. 276 00:21:00,760 --> 00:21:03,920 To my thinking, this changes everything. 277 00:21:05,200 --> 00:21:09,560 These underground labyrinths aren't just isolated, individual bunkers. 278 00:21:09,640 --> 00:21:12,720 They're part of a massive and widespread project 279 00:21:12,800 --> 00:21:16,560 involving dozens of similar sites scattered across the region. 280 00:21:17,640 --> 00:21:21,400 Only a highly motivated culture would have undertaken such a task. 281 00:21:23,760 --> 00:21:27,040 What kind of threat would have been so devastating 282 00:21:27,120 --> 00:21:30,240 that it could compel an entire people, 283 00:21:30,320 --> 00:21:35,200 possibly hundreds of thousands of them, to carve out a new life underground? 284 00:21:36,200 --> 00:21:39,240 There has to be another explanation for why these places were made 285 00:21:39,320 --> 00:21:43,120 which makes better sense than hiding from invading armies. 286 00:21:46,160 --> 00:21:50,160 The answer might lie in one of the region's very oldest myths, 287 00:21:51,320 --> 00:21:55,640 one that dates back thousands of years to the Zoroastrians. 288 00:21:56,440 --> 00:21:58,000 [folk music playing] 289 00:21:59,000 --> 00:22:02,600 These are some of Cappadocia's famous whirling dervishes. 290 00:22:07,280 --> 00:22:10,360 Devout followers of a religion called Sufism. 291 00:22:14,720 --> 00:22:18,320 One of the few remnants of the ancient culture of Zoroastrianism. 292 00:22:20,800 --> 00:22:25,200 The ancient Persian prophet, Zoroaster, founded what's claimed by some 293 00:22:25,280 --> 00:22:28,600 to be the world's oldest continuously practiced religion. 294 00:22:32,080 --> 00:22:37,000 Its sacred texts refer to an underground city just like Derinkuyu, 295 00:22:37,080 --> 00:22:41,280 telling us exactly why it was made and by whom. 296 00:22:41,800 --> 00:22:46,640 Zoroaster spoke of the first king and founder of civilization, 297 00:22:46,720 --> 00:22:48,080 a man named Yima. 298 00:22:54,000 --> 00:22:57,000 One day, as Yima was beside a river, 299 00:22:57,080 --> 00:23:01,720 the great god Ahura Mazda appeared to him with an ominous warning. 300 00:23:02,800 --> 00:23:06,080 Not of a flood, but of a fatal winter. 301 00:23:07,320 --> 00:23:12,160 And he told Yima to build a vara, an immense underground shelter. 302 00:23:14,040 --> 00:23:17,920 Into it, he must bring the best of men and women, and animals, 303 00:23:18,000 --> 00:23:19,280 two of every kind. 304 00:23:20,320 --> 00:23:23,600 Yima must store seeds of every tree and fruit, 305 00:23:23,680 --> 00:23:27,840 creating an inexhaustible supply until the fatal winter had passed. 306 00:23:28,720 --> 00:23:31,680 Oh, and the sacred texts also tell us 307 00:23:31,760 --> 00:23:37,080 that the onset of this fatal winter would be heralded by a serpent in the sky. 308 00:23:40,560 --> 00:23:42,720 The supposedly mythical vara 309 00:23:42,800 --> 00:23:46,760 sounds a lot like the underground cities we find here in Cappadocia. 310 00:23:47,800 --> 00:23:50,800 But mainstream historians refuse to see the connection. 311 00:23:51,920 --> 00:23:54,440 The Yima myth is just another one of those myths 312 00:23:54,520 --> 00:23:56,880 that archaeology assumes don't mean anything, 313 00:23:56,960 --> 00:24:00,480 and yet it speaks of a terrible freezing winter descending. 314 00:24:00,560 --> 00:24:02,440 [wind howling] 315 00:24:03,320 --> 00:24:05,480 And just as geologists have confirmed 316 00:24:05,560 --> 00:24:09,520 that there was a period of great floods during the Younger Dryas, 317 00:24:09,600 --> 00:24:12,080 much resembling those described in myths, 318 00:24:13,160 --> 00:24:17,240 they've also noted that afterward, temperatures around the planet plummeted. 319 00:24:18,520 --> 00:24:20,240 A fatal winter indeed. 320 00:24:21,800 --> 00:24:26,000 And then there's that detail linking the onset of the fatal winter 321 00:24:26,080 --> 00:24:29,000 to the arrival of a great snake out of the sky, 322 00:24:30,480 --> 00:24:34,520 just like the snakes we've encountered in the myths of the ancient Aztecs, 323 00:24:36,000 --> 00:24:37,560 or of the Iroquois. 324 00:24:37,640 --> 00:24:40,600 Serpents always associated with cataclysms. 325 00:24:46,120 --> 00:24:48,920 I'm also reminded of those pillars at Göbekli Tepe 326 00:24:49,000 --> 00:24:54,240 covered in carved depictions of snakes seemingly raining down from the sky. 327 00:24:55,160 --> 00:24:58,960 Or of the snake etched into Malta's great temple of Ġgantija. 328 00:24:59,920 --> 00:25:01,960 Or of Serpent Mound in North America. 329 00:25:02,880 --> 00:25:07,400 Of course, archaeologists don't connect these ancient symbols and traditions 330 00:25:07,480 --> 00:25:10,680 from opposite sides of the planet to one another at all, 331 00:25:10,760 --> 00:25:12,920 let alone to a singular event. 332 00:25:13,800 --> 00:25:18,000 But we've now seen how different and supposedly unrelated structures 333 00:25:18,080 --> 00:25:19,480 all around the world 334 00:25:19,560 --> 00:25:23,680 seem to have benefitted from a legacy of very ancient knowledge. 335 00:25:24,120 --> 00:25:26,560 A shared legacy of unknown origin. 336 00:25:27,760 --> 00:25:30,920 The stunning implication is that during the Ice Age, 337 00:25:31,000 --> 00:25:35,040 an advanced civilization, whose influence spanned the globe, 338 00:25:35,120 --> 00:25:39,560 coexisted with the hunter-gatherers who we know were also present at that time. 339 00:25:40,360 --> 00:25:42,520 A civilization that was destroyed 340 00:25:42,600 --> 00:25:45,520 in the mysterious cataclysms of the Younger Dryas. 341 00:25:47,480 --> 00:25:52,000 Could all these references to serpents also be part of that legacy? 342 00:25:52,920 --> 00:25:56,320 A warning left behind by survivors. 343 00:26:04,160 --> 00:26:11,040 What it comes down to, for me, is that we humans are a species with amnesia. 344 00:26:12,440 --> 00:26:15,480 So badly knocked on the head by the cataclysms that occurred 345 00:26:15,560 --> 00:26:17,520 at the end of the last Ice Age, 346 00:26:17,600 --> 00:26:21,680 that we've forgotten an important chapter of our own story. 347 00:26:23,000 --> 00:26:28,200 And that can be a big problem because as with so many of these myths, 348 00:26:28,280 --> 00:26:32,760 a later story about Yima ends with a clear warning from the gods 349 00:26:32,840 --> 00:26:36,200 that one day, a similar catastrophe would return. 350 00:26:36,280 --> 00:26:38,000 [thunderclap] 351 00:26:39,120 --> 00:26:40,080 Could it? 352 00:26:41,800 --> 00:26:46,720 For a long time, it remained a mystery as to what triggered the floods, 353 00:26:46,800 --> 00:26:50,160 fires and plunging temperatures of the Younger Dryas, 354 00:26:51,080 --> 00:26:55,120 but new geological evidence has suggested a terrible possibility. 355 00:26:56,440 --> 00:26:58,760 Evidence still visible today 356 00:26:58,840 --> 00:27:01,840 in the scarred landscape of prehistoric America, 357 00:27:01,920 --> 00:27:03,440 where I'm headed next. 358 00:27:04,440 --> 00:27:08,320 I'm quite persuaded that the origin of serpent symbolism 359 00:27:08,400 --> 00:27:11,160 has to do precisely with those serpents in the sky 360 00:27:11,240 --> 00:27:12,840 that we call comets.