1
00:00:14,083 --> 00:00:17,803
[Graham] What I'm suggesting is that
something that we would recognize

2
00:00:17,883 --> 00:00:22,163
as an advanced civilization
existed during the Ice Age.

3
00:00:23,003 --> 00:00:25,683
I'm not saying that they flew to the moon.

4
00:00:29,883 --> 00:00:33,963
But what I'm saying is that they were
far, far, far more advanced

5
00:00:34,043 --> 00:00:35,843
in terms of scientific knowledge.

6
00:00:38,123 --> 00:00:40,963
Knowledge of the Earth,
knowledge of the universe,

7
00:00:41,043 --> 00:00:42,603
than we're taught.

8
00:00:44,843 --> 00:00:48,083
And capable of
astounding feats of engineering,

9
00:00:49,363 --> 00:00:52,763
like the site I'm heading to
in Turkey's Cappadocia region.

10
00:00:54,443 --> 00:00:58,483
There's an ancient survival bunker
deep underground…

11
00:01:02,083 --> 00:01:06,483
built not just to shelter a few people,
but to shelter thousands.

12
00:01:08,243 --> 00:01:11,883
Mainstream historians
have long debated its purpose,

13
00:01:11,963 --> 00:01:14,523
but I believe it might just explain

14
00:01:14,603 --> 00:01:19,843
how this lost ancient civilization
I've been looking for became lost.

15
00:01:21,163 --> 00:01:24,203
This is the story of Derinkuyu.

16
00:01:42,723 --> 00:01:47,003
I've come to a region of Turkey
known as Cappadocia.

17
00:01:49,603 --> 00:01:55,923
About 240 miles northwest of those
mysterious enclosures of Göbekli Tepe…

18
00:01:57,363 --> 00:01:59,523
that were intentionally buried,

19
00:02:01,083 --> 00:02:05,763
memorializing a time of great cataclysms
at the end of the Ice Age.

20
00:02:09,483 --> 00:02:13,643
Millions of years ago,
this region's landscape was transformed

21
00:02:13,723 --> 00:02:20,363
by a series of volcanic eruptions,
leaving layer upon layer of ash,

22
00:02:20,443 --> 00:02:25,203
which compressed over millennia
into a soft stone called tuff.

23
00:02:26,963 --> 00:02:29,763
A stone easily shaped by the elements,

24
00:02:29,843 --> 00:02:32,803
creating what locals call
"fairy chimneys."

25
00:02:33,923 --> 00:02:37,243
But a stone that also
allowed the construction

26
00:02:37,323 --> 00:02:41,083
of one of the most remarkable
large-scale projects

27
00:02:41,163 --> 00:02:46,203
humanity has ever embarked upon
deep beneath this soft rock.

28
00:02:47,283 --> 00:02:49,403
Just a few miles from where I stand,

29
00:02:49,483 --> 00:02:54,483
the mysterious hidden city created
thousands of years ago has been revealed.

30
00:02:54,563 --> 00:02:57,883
It's the work of
an as-yet unidentified civilization

31
00:02:57,963 --> 00:03:00,563
that was clearly motivated by fear.

32
00:03:00,643 --> 00:03:03,803
The big question therefore is,
fear of what?

33
00:03:14,563 --> 00:03:18,203
The closest town,
Derinkuyu, seems unremarkable.

34
00:03:20,843 --> 00:03:26,363
But in 1963, developers renovating
a house here knocked through a floor,

35
00:03:27,963 --> 00:03:33,923
only to discover a deep tunnel,
one that led to a forgotten world.

36
00:03:35,403 --> 00:03:39,403
It's hard to believe, as you walk
the dusty streets of this small town,

37
00:03:39,883 --> 00:03:43,283
that carved out of the living bedrock
right beneath my feet

38
00:03:43,883 --> 00:03:47,643
is an ancient, immense
and mysterious subterranean complex.

39
00:03:50,883 --> 00:03:54,243
If you're claustrophobic,
consider yourself warned.

40
00:03:57,003 --> 00:03:58,763
We're headed underground.

41
00:04:06,083 --> 00:04:09,123
This is the underground city of Derinkuyu.

42
00:04:12,763 --> 00:04:15,603
A series of stone tunnels and chambers

43
00:04:15,683 --> 00:04:19,083
plunging as deep
as 85 meters below the surface…

44
00:04:21,322 --> 00:04:24,083
creating 18 levels of rooms and tunnels.

45
00:04:26,882 --> 00:04:31,363
The entire complex
was hacked out of the rock with hand axes.

46
00:04:32,723 --> 00:04:34,883
A disorientating warren

47
00:04:34,963 --> 00:04:38,003
that occasionally widens
into large open spaces.

48
00:04:39,123 --> 00:04:44,243
From inside, it's virtually impossible
to get a sense of the scale of the place.

49
00:04:45,723 --> 00:04:48,483
But most of this underground city
has been mapped,

50
00:04:50,043 --> 00:04:52,963
and if we take away the rock
between the spaces,

51
00:04:53,763 --> 00:04:55,883
we can see a cross section of the city,

52
00:04:57,243 --> 00:04:59,043
and it's utterly astounding.

53
00:05:02,643 --> 00:05:09,163
It's an ant farm built human size,
with subterranean caves and tunnels

54
00:05:09,243 --> 00:05:12,723
extending over an area
of four square kilometers.

55
00:05:14,203 --> 00:05:20,043
To keep it well-ventilated,
Derinkuyu has upwards of 15,000 air ducts

56
00:05:20,123 --> 00:05:22,403
connecting the upper levels
to the surface…

57
00:05:25,243 --> 00:05:27,803
and more than 50 vertical shafts,

58
00:05:27,883 --> 00:05:32,763
some stretching all the way down to the
water table 85 meters below the surface…

59
00:05:36,323 --> 00:05:38,363
giving the complex its name.

60
00:05:38,443 --> 00:05:41,163
Derinkuyu means, "deep well."

61
00:05:45,083 --> 00:05:48,523
Stunning in its ingenuity
and architectural complexity,

62
00:05:48,603 --> 00:05:53,683
it's calculated that Derinkuyu
could shelter up to 20,000 people.

63
00:05:54,363 --> 00:05:55,603
But questions remain.

64
00:05:56,283 --> 00:05:59,563
Which people, when and why?

65
00:06:02,643 --> 00:06:04,403
It's hard to know precisely,

66
00:06:05,123 --> 00:06:09,883
because Derinkuyu is like a crime scene
that's been trampled on for generations.

67
00:06:13,323 --> 00:06:16,083
Many cultures have passed through
this part of Turkey.

68
00:06:17,043 --> 00:06:21,283
For centuries, Cappadocia occupied
a place of strategic importance,

69
00:06:22,443 --> 00:06:26,963
along the legendary Silk Road
that connected Asia to Europe,

70
00:06:27,603 --> 00:06:29,923
going back to the time
of Alexander the Great.

71
00:06:32,323 --> 00:06:34,523
Turkish scholar, Sevim Tunçdemir,

72
00:06:34,603 --> 00:06:38,483
is an expert on the Derinkuyu tunnels
and their various occupants.

73
00:06:39,003 --> 00:06:41,683
[in Turkish] This region has been home
to many civilizations.

74
00:06:41,763 --> 00:06:45,123
If we count them
starting from the beginning,

75
00:06:45,803 --> 00:06:47,483
there were the Hittites,

76
00:06:47,563 --> 00:06:50,123
then there were the Phrygians,
then the Persians,

77
00:06:50,963 --> 00:06:52,643
the Cappadocian kingdom,

78
00:06:52,723 --> 00:06:54,123
the Roman Empire.

79
00:06:54,203 --> 00:06:57,003
All the people
who passed through used them.

80
00:06:57,563 --> 00:07:02,363
They were even in use
up until the Ottoman period.

81
00:07:04,843 --> 00:07:06,803
[Graham] When the tunnels
were first discovered,

82
00:07:06,883 --> 00:07:10,483
archaeologists found artifacts
left by early Christians,

83
00:07:12,043 --> 00:07:15,243
and in the deepest levels,
secret meeting rooms

84
00:07:15,323 --> 00:07:18,243
carved out with
vaulted ceilings like churches.

85
00:07:19,843 --> 00:07:21,403
So the original theory,

86
00:07:21,483 --> 00:07:24,123
which many historians
still cling to today,

87
00:07:24,723 --> 00:07:26,723
was that the tunnels beneath Derinkuyu

88
00:07:26,803 --> 00:07:30,243
were carved out by Christians
in the 7th century AD,

89
00:07:32,243 --> 00:07:34,963
trying to hide from Arab raiding parties.

90
00:07:36,483 --> 00:07:38,963
It's a tale
that appeals to Western tourists.

91
00:07:39,923 --> 00:07:42,243
Also, it's totally wrong.

92
00:07:45,203 --> 00:07:49,323
Later excavations found evidence
of people using this underground city

93
00:07:49,403 --> 00:07:52,043
as early as the 8th century BC,

94
00:07:52,643 --> 00:07:55,763
hundreds of years before
the Christians were here.

95
00:07:57,883 --> 00:08:01,803
We encounter this again and again
on archaeological sites around the world.

96
00:08:01,883 --> 00:08:06,283
There's a big notice based on
the received wisdom of archaeologists,

97
00:08:06,363 --> 00:08:09,043
and again and again that notice is wrong.

98
00:08:09,803 --> 00:08:11,083
Factually wrong.

99
00:08:11,163 --> 00:08:14,683
Proved to be wrong
by later excavations and yet not changed.

100
00:08:15,243 --> 00:08:18,643
Don't trust the noticeboards.
Do the legwork yourself.

101
00:08:18,723 --> 00:08:21,243
Don't rely on the so-called experts.

102
00:08:25,123 --> 00:08:28,443
There were many cultures
who used these tunnels over centuries,

103
00:08:29,523 --> 00:08:33,323
but what I want to know
is who began this remarkable project.

104
00:08:34,483 --> 00:08:36,403
How far back does it go?

105
00:08:38,443 --> 00:08:43,722
Historian Hüsam Süleymangil has been
investigating this site for decades,

106
00:08:43,803 --> 00:08:46,443
trying to unlock its mysterious origins.

107
00:08:47,763 --> 00:08:53,763
So, when I look at Derinkuyu
and the complexity of it, I am mystified.

108
00:08:53,843 --> 00:08:57,723
When do you think
that this project started?

109
00:08:57,803 --> 00:08:59,883
There are several
different theories about it

110
00:08:59,963 --> 00:09:02,803
and none of them
is really proven by science.

111
00:09:02,883 --> 00:09:03,723
Right.

112
00:09:03,803 --> 00:09:05,843
They couldn't find
any written information.

113
00:09:05,923 --> 00:09:09,963
They couldn't find any organic material
to use to carbon date.

114
00:09:10,043 --> 00:09:11,523
Are there any carbon dates at all?

115
00:09:11,603 --> 00:09:13,803
As far as I know,
there is no carbon dating.

116
00:09:13,883 --> 00:09:14,723
That's extraordinary.

117
00:09:14,803 --> 00:09:17,283
So, the date is still a big mystery.

118
00:09:21,443 --> 00:09:23,443
I have my own theories,

119
00:09:23,523 --> 00:09:25,203
but Hüsam proposes a date

120
00:09:25,283 --> 00:09:29,043
based on the oldest known culture
to use these caves.

121
00:09:29,843 --> 00:09:32,083
Most plausible theory,
according to my mind,

122
00:09:32,163 --> 00:09:35,403
is actually about the 8th century BC.

123
00:09:37,243 --> 00:09:39,203
[Graham] At that time,
this part of the world

124
00:09:39,283 --> 00:09:42,323
was inhabited by a people
known as the Phrygians,

125
00:09:43,443 --> 00:09:47,083
who were under threat
from another empire, the Assyrians.

126
00:09:49,043 --> 00:09:53,003
We know that there was a big Assyrian army
coming from southeast.

127
00:09:55,283 --> 00:09:59,163
[Graham] The Phrygians would've viewed
the invading army with sheer terror.

128
00:10:02,203 --> 00:10:05,283
The Assyrians were notorious
for skinning prisoners,

129
00:10:05,843 --> 00:10:09,683
impaling them and burning children alive.

130
00:10:12,843 --> 00:10:14,363
According to later accounts,

131
00:10:14,443 --> 00:10:18,043
when the Assyrian invaders
marched against the people in this valley,

132
00:10:18,683 --> 00:10:22,323
they were surprised
by the defenders' innovative tactics.

133
00:10:27,963 --> 00:10:31,283
[Hüsam] The Phrygians were fighting
against the Assyrian army

134
00:10:31,363 --> 00:10:32,883
in the guerilla type of warfare,

135
00:10:32,963 --> 00:10:35,483
attacking the army
in sort of unexpected places.

136
00:10:35,563 --> 00:10:37,043
When the army start to chase them,

137
00:10:37,123 --> 00:10:39,723
they would come
and use these as hideout places.

138
00:10:42,643 --> 00:10:45,563
[Graham] It's a time-honored strategy
in guerrilla warfare.

139
00:10:47,883 --> 00:10:51,363
Similar tunnels were dug out
by the Viet Cong in South Vietnam.

140
00:10:52,723 --> 00:10:54,923
And Afghan rebels did the same

141
00:10:55,443 --> 00:10:59,243
to hide from superior Soviet
and then American invading forces.

142
00:11:01,963 --> 00:11:03,523
This official position,

143
00:11:03,603 --> 00:11:07,443
that the Phrygians dug out these tunnels
as a secret military base,

144
00:11:08,123 --> 00:11:11,963
seems to be supported by
one of the complex's more clever features…

145
00:11:14,123 --> 00:11:17,563
massive stone discs
that can be rolled into place,

146
00:11:17,643 --> 00:11:19,163
sealing up the passageways.

147
00:11:22,203 --> 00:11:26,003
These rolling doors
have a diameter of up to five feet

148
00:11:26,683 --> 00:11:28,243
and can weigh up to half a ton.

149
00:11:32,523 --> 00:11:35,603
On the inside surface,
the disc has a hole.

150
00:11:36,563 --> 00:11:41,443
Insert a smaller locking stone as a handle
and you can roll the door shut,

151
00:11:42,403 --> 00:11:46,083
creating a smooth, formidable barrier
for anyone on the other side.

152
00:11:54,603 --> 00:11:58,403
But did the Phrygians
really make these ingenious doors,

153
00:11:59,683 --> 00:12:01,603
or were they already here?

154
00:12:03,563 --> 00:12:05,923
They're carved
from the same compressed ash

155
00:12:06,003 --> 00:12:07,683
that made the fairy chimneys.

156
00:12:11,643 --> 00:12:16,763
The same soft rock that allowed someone
to dig all this out in the first place.

157
00:12:18,923 --> 00:12:22,763
They're certainly sealable doors,
separating the levels from each other,

158
00:12:22,843 --> 00:12:26,403
requiring sophisticated engineering
to fit in place.

159
00:12:26,483 --> 00:12:28,123
But the stone is soft

160
00:12:28,203 --> 00:12:31,203
and determined attackers
armed with sledgehammers and chisels

161
00:12:31,283 --> 00:12:33,163
could easily have broken through,

162
00:12:33,243 --> 00:12:37,443
rendering all the effort to make
these megaliths completely useless.

163
00:12:37,523 --> 00:12:41,523
I'm beginning to wonder if they were
designed to deter human attackers at all.

164
00:12:44,283 --> 00:12:48,123
To me, these look less
like defensive fortifications

165
00:12:48,203 --> 00:12:51,643
and more like a clever way
to allow privacy between sections,

166
00:12:53,243 --> 00:12:55,243
or to prevent fires from spreading.

167
00:12:57,603 --> 00:13:02,123
Even if this place was originally built
as a military installation,

168
00:13:02,203 --> 00:13:04,043
why dig it out here?

169
00:13:06,043 --> 00:13:07,883
There was nothing here to defend.

170
00:13:09,683 --> 00:13:11,603
[Sevim, in Turkish]
There were no settlements

171
00:13:12,283 --> 00:13:16,723
above ground in Derinkuyu until 1830.

172
00:13:21,563 --> 00:13:26,123
The notion that these are places where
people went to hide from invading armies

173
00:13:26,203 --> 00:13:27,883
makes very little sense to me.

174
00:13:27,963 --> 00:13:30,603
When an invading army
comes into a territory,

175
00:13:30,683 --> 00:13:33,443
they come to take,
possess and occupy that territory.

176
00:13:33,523 --> 00:13:37,323
All they have to do is block the entrances
and wait till you die of starvation.

177
00:13:38,203 --> 00:13:41,203
So that idea
just doesn't make any sense at all.

178
00:13:42,323 --> 00:13:45,563
See, in my opinion,
I think scholarship is going too far

179
00:13:45,643 --> 00:13:47,603
to say this was the 8th century BC

180
00:13:47,683 --> 00:13:50,843
because those are the earliest dates
that we find people using it.

181
00:13:50,923 --> 00:13:51,883
Right.

182
00:13:51,963 --> 00:13:54,843
But that we don't necessarily know
that they made it then.

183
00:13:54,923 --> 00:13:56,843
Maybe it was already made.

184
00:13:56,923 --> 00:13:58,723
Quite possible, as it's still a mystery.

185
00:13:58,803 --> 00:14:00,803
-It's just the most plausible theory…
-Yes.

186
00:14:00,883 --> 00:14:02,723
…not the only correct theory.

187
00:14:07,643 --> 00:14:09,563
[Graham] The dating
of this underground city

188
00:14:09,643 --> 00:14:13,523
is about as insecure as it's possible
for archaeological dating to be.

189
00:14:15,363 --> 00:14:19,523
All the proposed dates derive from
use of the structure at different periods.

190
00:14:19,603 --> 00:14:21,763
The fact that I live in a house today

191
00:14:21,843 --> 00:14:24,163
doesn't mean it was built
immediately before I moved in.

192
00:14:32,363 --> 00:14:36,563
It's a notion that leads me to question
the official dating of these tunnels.

193
00:14:37,723 --> 00:14:39,163
Could they be older,

194
00:14:39,963 --> 00:14:43,363
much older, than the accepted theory says?

195
00:14:45,363 --> 00:14:50,443
And was the reason for their construction
not to hide from an invading army

196
00:14:51,963 --> 00:14:53,963
but to hide from something else?

197
00:14:56,323 --> 00:15:00,363
In the most ancient levels,
the ones closest to the surface,

198
00:15:00,443 --> 00:15:03,283
the chambers seem
not to be designed for defense

199
00:15:03,363 --> 00:15:04,643
but for everyday living.

200
00:15:08,283 --> 00:15:14,363
[in Turkish] The underground cities were
organized to cater for human living.

201
00:15:14,443 --> 00:15:17,843
In other words, for daily life.

202
00:15:19,083 --> 00:15:21,683
And for this,
all the resources were available.

203
00:15:23,203 --> 00:15:28,083
Starting with the kitchen,
to the pantry, to the living spaces.

204
00:15:30,683 --> 00:15:34,043
[in English] There are sections
we know that they would use as cooking

205
00:15:34,123 --> 00:15:36,683
and we know
that they created small chimneys.

206
00:15:36,763 --> 00:15:37,723
Mmm-hmm.

207
00:15:37,803 --> 00:15:41,243
At the entrance floors, there are
some rooms that's named as stables.

208
00:15:41,883 --> 00:15:45,563
Animals would be the most valuable
belongings of those people.

209
00:15:48,643 --> 00:15:51,763
[Graham] One area has even been identified
as an ancient winery

210
00:15:52,363 --> 00:15:53,803
where grapes were crushed.

211
00:15:55,883 --> 00:15:58,723
Indeed, the tunnels
would make a great wine cellar.

212
00:15:59,643 --> 00:16:01,523
The temperature stays quite comfortable,

213
00:16:01,603 --> 00:16:04,883
no matter how hot or cold
it gets on the surface.

214
00:16:06,203 --> 00:16:08,603
Food would've stayed fresh
longer down here.

215
00:16:10,963 --> 00:16:16,723
It's clear that Derinkuyu was created
to be used by a substantial population.

216
00:16:17,643 --> 00:16:18,843
An underground bunker.

217
00:16:22,843 --> 00:16:24,563
Think about all the modern examples

218
00:16:24,643 --> 00:16:28,483
where humans have created
vast underground living spaces.

219
00:16:29,283 --> 00:16:31,643
The Cheyenne Mountain Complex in Colorado.

220
00:16:34,123 --> 00:16:38,283
The Dixia Cheng network of tunnels
dug out beneath Beijing.

221
00:16:39,843 --> 00:16:43,563
The Presidential Emergency
Operations Center under the White House.

222
00:16:45,123 --> 00:16:48,643
None of these were built
to defend against invading armies.

223
00:16:49,963 --> 00:16:52,163
They were built as places of refuge,

224
00:16:52,243 --> 00:16:55,843
to preserve life in the event
of some kind of threat from above.

225
00:16:58,043 --> 00:17:00,843
I think that's exactly what's going on…

226
00:17:04,083 --> 00:17:05,323
at Derinkuyu.

227
00:17:07,803 --> 00:17:11,362
But I also believe this bunker
was created much longer ago

228
00:17:11,443 --> 00:17:13,963
than archaeologists
are willing to consider.

229
00:17:15,642 --> 00:17:17,443
There is evidence that suggests

230
00:17:17,523 --> 00:17:20,803
that Derinkuyu may go back
as far as the last Ice Age.

231
00:17:25,362 --> 00:17:29,402
It concerns those telltale marks
left by hand axes

232
00:17:29,483 --> 00:17:31,083
on the walls of Derinkuyu.

233
00:17:32,803 --> 00:17:35,163
Just a mile outside Derinkuyu,

234
00:17:35,243 --> 00:17:38,723
Turkish archaeologists
exploring an ancient riverbed

235
00:17:38,803 --> 00:17:41,603
found several hand axes and stone tools

236
00:17:42,203 --> 00:17:46,643
dating back to around 9500 BC,

237
00:17:47,843 --> 00:17:49,443
the end of the last Ice Age.

238
00:17:50,243 --> 00:17:51,563
The same sort of tools

239
00:17:51,643 --> 00:17:55,603
that shaped Derinkuyu's
shallowest and oldest chambers.

240
00:17:59,243 --> 00:18:02,963
Think about the semi-subterranean chamber
at Karahan Tepe,

241
00:18:03,043 --> 00:18:05,363
less than 300 miles from here,

242
00:18:06,083 --> 00:18:08,123
with its columns that closely resemble

243
00:18:08,203 --> 00:18:11,363
the natural fairy chimney formations
of Cappadocia.

244
00:18:14,203 --> 00:18:15,483
Since no one disputes

245
00:18:15,563 --> 00:18:18,843
that this chamber was carved out
at the end of the last Ice Age,

246
00:18:20,803 --> 00:18:22,443
there's no reason why Derinkuyu

247
00:18:22,523 --> 00:18:24,963
couldn't have been made
at around the same time.

248
00:18:30,003 --> 00:18:33,123
As Derinkuyu reveals
its depth and complexity,

249
00:18:33,203 --> 00:18:37,443
what's hard to ignore
is the vast scale of the enterprise

250
00:18:38,603 --> 00:18:43,083
and the enormous effort involved
in tunneling it out in the first place.

251
00:18:45,643 --> 00:18:48,843
What makes this feat of engineering
even more remarkable

252
00:18:49,563 --> 00:18:53,123
is that this isn't the only
underground city in Cappadocia.

253
00:18:58,243 --> 00:19:01,083
In 2013,
construction workers stumbled across

254
00:19:01,163 --> 00:19:03,443
another series of tunnels at Nevşehir,

255
00:19:05,403 --> 00:19:07,043
17 miles away.

256
00:19:08,083 --> 00:19:11,923
What they found was an underground city
that's even larger than Derinkuyu.

257
00:19:14,843 --> 00:19:17,883
Since then, more underground cities
have been discovered.

258
00:19:21,083 --> 00:19:24,163
The stunning truth is here in Cappadocia,

259
00:19:24,243 --> 00:19:28,923
archaeologists have identified
36 such underground cities.

260
00:19:32,603 --> 00:19:35,123
And if we count the ones
with just two levels,

261
00:19:35,643 --> 00:19:37,803
that number balloons to 200.

262
00:19:43,243 --> 00:19:47,203
One of these underground cities,
just five miles away from Derinkuyu,

263
00:19:47,283 --> 00:19:49,443
holds an incredible secret.

264
00:19:51,283 --> 00:19:54,043
The tunnels at Kaymakli
run eight stories deep

265
00:19:54,123 --> 00:19:56,883
over an area wider than Derinkuyu.

266
00:19:58,963 --> 00:20:02,683
Based on the number of storage chambers
carved into the walls,

267
00:20:02,763 --> 00:20:08,243
archaeologists think this bunker
could've supported up to 3,500 people.

268
00:20:12,643 --> 00:20:18,363
But Kaymakli's most mind-blowing feature
can be found here on the third level down.

269
00:20:22,963 --> 00:20:26,363
An underground tunnel
that runs far into the distance.

270
00:20:32,243 --> 00:20:33,883
It's impassable today,

271
00:20:33,963 --> 00:20:39,043
but this blocked tunnel is claimed by some
to connect Kaymakli to Derinkuyu.

272
00:20:41,323 --> 00:20:43,883
A straight-line distance
of about five miles.

273
00:20:48,843 --> 00:20:51,323
In fact, archaeologists have confirmed

274
00:20:51,403 --> 00:20:55,443
that at least six other
underground complexes in Cappadocia

275
00:20:55,523 --> 00:20:59,083
are connected to one another
by similar underground passages.

276
00:21:00,803 --> 00:21:03,963
To my thinking, this changes everything.

277
00:21:05,243 --> 00:21:09,603
These underground labyrinths
aren't just isolated, individual bunkers.

278
00:21:09,683 --> 00:21:12,763
They're part of
a massive and widespread project

279
00:21:12,843 --> 00:21:16,603
involving dozens of similar sites
scattered across the region.

280
00:21:17,683 --> 00:21:21,443
Only a highly motivated culture
would have undertaken such a task.

281
00:21:23,803 --> 00:21:27,083
What kind of threat
would have been so devastating

282
00:21:27,163 --> 00:21:30,283
that it could compel an entire people,

283
00:21:30,363 --> 00:21:35,243
possibly hundreds of thousands of them,
to carve out a new life underground?

284
00:21:36,243 --> 00:21:39,283
There has to be another explanation
for why these places were made

285
00:21:39,363 --> 00:21:43,163
which makes better sense
than hiding from invading armies.

286
00:21:46,203 --> 00:21:50,203
The answer might lie
in one of the region's very oldest myths,

287
00:21:51,363 --> 00:21:55,683
one that dates back thousands of years
to the Zoroastrians.

288
00:21:56,483 --> 00:21:58,043
[folk music playing]

289
00:21:59,043 --> 00:22:02,643
These are some of Cappadocia's
famous whirling dervishes.

290
00:22:07,323 --> 00:22:10,403
Devout followers
of a religion called Sufism.

291
00:22:14,763 --> 00:22:18,363
One of the few remnants
of the ancient culture of Zoroastrianism.

292
00:22:20,843 --> 00:22:25,243
The ancient Persian prophet, Zoroaster,
founded what's claimed by some

293
00:22:25,323 --> 00:22:28,643
to be the world's oldest
continuously practiced religion.

294
00:22:32,123 --> 00:22:37,043
Its sacred texts refer to
an underground city just like Derinkuyu,

295
00:22:37,123 --> 00:22:41,323
telling us exactly
why it was made and by whom.

296
00:22:41,843 --> 00:22:46,683
Zoroaster spoke of the first king
and founder of civilization,

297
00:22:46,763 --> 00:22:48,123
a man named Yima.

298
00:22:54,043 --> 00:22:57,043
One day, as Yima was beside a river,

299
00:22:57,123 --> 00:23:01,763
the great god Ahura Mazda
appeared to him with an ominous warning.

300
00:23:02,843 --> 00:23:06,123
Not of a flood, but of a fatal winter.

301
00:23:07,363 --> 00:23:12,203
And he told Yima to build a vara,
an immense underground shelter.

302
00:23:14,083 --> 00:23:17,963
Into it, he must bring the best
of men and women, and animals,

303
00:23:18,043 --> 00:23:19,323
two of every kind.

304
00:23:20,363 --> 00:23:23,643
Yima must store seeds
of every tree and fruit,

305
00:23:23,723 --> 00:23:27,883
creating an inexhaustible supply
until the fatal winter had passed.

306
00:23:28,763 --> 00:23:31,723
Oh, and the sacred texts also tell us

307
00:23:31,803 --> 00:23:37,123
that the onset of this fatal winter
would be heralded by a serpent in the sky.

308
00:23:40,603 --> 00:23:42,763
The supposedly mythical vara

309
00:23:42,843 --> 00:23:46,803
sounds a lot like the underground cities
we find here in Cappadocia.

310
00:23:47,843 --> 00:23:50,843
But mainstream historians
refuse to see the connection.

311
00:23:51,963 --> 00:23:54,483
The Yima myth
is just another one of those myths

312
00:23:54,563 --> 00:23:56,923
that archaeology assumes
don't mean anything,

313
00:23:57,003 --> 00:24:00,523
and yet it speaks of
a terrible freezing winter descending.

314
00:24:00,603 --> 00:24:02,483
[wind howling]

315
00:24:03,363 --> 00:24:05,523
And just as geologists have confirmed

316
00:24:05,603 --> 00:24:09,563
that there was a period of great floods
during the Younger Dryas,

317
00:24:09,643 --> 00:24:12,123
much resembling those described in myths,

318
00:24:13,203 --> 00:24:17,283
they've also noted that afterward,
temperatures around the planet plummeted.

319
00:24:18,563 --> 00:24:20,283
A fatal winter indeed.

320
00:24:21,843 --> 00:24:26,043
And then there's that detail
linking the onset of the fatal winter

321
00:24:26,123 --> 00:24:29,043
to the arrival
of a great snake out of the sky,

322
00:24:30,523 --> 00:24:34,563
just like the snakes we've encountered
in the myths of the ancient Aztecs,

323
00:24:36,043 --> 00:24:37,603
or of the Iroquois.

324
00:24:37,683 --> 00:24:40,643
Serpents always
associated with cataclysms.

325
00:24:46,163 --> 00:24:48,963
I'm also reminded
of those pillars at Göbekli Tepe

326
00:24:49,043 --> 00:24:54,283
covered in carved depictions of snakes
seemingly raining down from the sky.

327
00:24:55,203 --> 00:24:59,003
Or of the snake etched into
Malta's great temple of Ġgantija.

328
00:24:59,963 --> 00:25:02,003
Or of Serpent Mound in North America.

329
00:25:02,923 --> 00:25:07,443
Of course, archaeologists don't connect
these ancient symbols and traditions

330
00:25:07,523 --> 00:25:10,723
from opposite sides of the planet
to one another at all,

331
00:25:10,803 --> 00:25:12,963
let alone to a singular event.

332
00:25:13,843 --> 00:25:18,043
But we've now seen how different
and supposedly unrelated structures

333
00:25:18,123 --> 00:25:19,523
all around the world

334
00:25:19,603 --> 00:25:23,723
seem to have benefitted from a legacy
of very ancient knowledge.

335
00:25:24,163 --> 00:25:26,603
A shared legacy of unknown origin.

336
00:25:27,803 --> 00:25:30,963
The stunning implication
is that during the Ice Age,

337
00:25:31,043 --> 00:25:35,083
an advanced civilization,
whose influence spanned the globe,

338
00:25:35,163 --> 00:25:39,603
coexisted with the hunter-gatherers who
we know were also present at that time.

339
00:25:40,403 --> 00:25:42,563
A civilization that was destroyed

340
00:25:42,643 --> 00:25:45,563
in the mysterious cataclysms
of the Younger Dryas.

341
00:25:47,523 --> 00:25:52,043
Could all these references to serpents
also be part of that legacy?

342
00:25:52,963 --> 00:25:56,363
A warning left behind by survivors.

343
00:26:04,203 --> 00:26:11,083
What it comes down to, for me, is that
we humans are a species with amnesia.

344
00:26:12,483 --> 00:26:15,523
So badly knocked on the head
by the cataclysms that occurred

345
00:26:15,603 --> 00:26:17,563
at the end of the last Ice Age,

346
00:26:17,643 --> 00:26:21,723
that we've forgotten
an important chapter of our own story.

347
00:26:23,043 --> 00:26:28,243
And that can be a big problem
because as with so many of these myths,

348
00:26:28,323 --> 00:26:32,803
a later story about Yima
ends with a clear warning from the gods

349
00:26:32,883 --> 00:26:36,243
that one day,
a similar catastrophe would return.

350
00:26:36,323 --> 00:26:38,043
[thunderclap]

351
00:26:39,163 --> 00:26:40,123
Could it?

352
00:26:41,843 --> 00:26:46,763
For a long time, it remained a mystery
as to what triggered the floods,

353
00:26:46,843 --> 00:26:50,203
fires and plunging temperatures
of the Younger Dryas,

354
00:26:51,123 --> 00:26:55,163
but new geological evidence
has suggested a terrible possibility.

355
00:26:56,483 --> 00:26:58,803
Evidence still visible today

356
00:26:58,883 --> 00:27:01,883
in the scarred landscape
of prehistoric America,

357
00:27:01,963 --> 00:27:03,483
where I'm headed next.

358
00:27:04,483 --> 00:27:08,363
I'm quite persuaded
that the origin of serpent symbolism

359
00:27:08,443 --> 00:27:11,203
has to do precisely
with those serpents in the sky

360
00:27:11,283 --> 00:27:12,883
that we call comets.