Byzantine Bunkers

At the risk of starting this story too early it’s necessary to understand the geography of the region to understand how it shaped the cultures that inhabited it.  Cappadocia lies in a region of violent geological activity where the Anatolian and Eurasian tectonic plates are slowly grinding against one another.  The current landscape of Cappadocia began taking shape in the Miocene geological period about 20 million years ago with the volcanic outpouring of massive deposits of solidified lava, ash and tuff stone. Over the following millennia rainfall and erosion have carved deep ravines and basins in the basalt leaving behind isolated pinnacles of rock.

From VolcanoCafe;

These structures, known as ‘fairy chimneys’, are weathering product, where relatively soft, less consolidated airfall ash is capped by resistant welded tuffs or lavas, the ‘cap’ being the latter material that has protected the ash from weathering. A closer inspection of these mushrooms, shows the ‘stem’ to be of fine grained variably stratified ash. Where sufficiently thick, these features have been easily excavated and make for excellent, if different dwellings.

Because the rock here is comparatively soft it can also be carved out with stone tools so human beings have been creating and expanding natural caverns in the region for tens of thousands of years. The first recorded civilisation to have settled here were colonists from the Assyrian kingdom to the east closely followed by Hittite settlers who inhabited the area in the 19th and 18th century BC.

Anatolia, the region where Cappadocia resides, has perpetually been a frontier for various empires. Mediterranean Greeks, Romans and Byzantines settled on the coast and fought protracted wars with Persian, Parthians and Arab kingdoms respectively.  The Wikipedia entry for the History of Anatolia is pretty much a role call of ancient civilisations.  As such, Cappadocia has been a sort of demilitarised zone between ferocious territorial powers and it shows in the archaeological record. The region is dotted with observation posts and honeycombed with caves and bolt-holes where people could seek refuge when invaders appeared on the horizon. Some of the cave systems are incredibly sophisticated and include layered defences, wells, kitchens, breweries, stables, places of worship and shelter for hundreds of people.

In 2007 author Alan Wiseman mentions the cave cities in a book about the traces of human civilisation that will remain once humans become extinct;

No one knows how many underground cities lie beneath Cappadocia. Eight have been discovered, and many smaller villages, but there are doubtless more. The biggest, Derinkuyu, wasn’t discovered until 1965, when a resident cleaning the back wall of his cave house broke through and discovered a room that he’d never seen, which led to still another, and another. Eventually, spelunking archeologists found a maze of connecting chambers that descended at least 18 stories and 280 feet beneath the surface, ample enough to hold 30,000 people – and much remains to be excavated. One tunnel, wide enough for three people walking abreast, connects to another underground town six miles away. Other passages suggest that at one time all of Cappadocia, above and below the ground, was linked by a hidden network. Many still use the tunnels of this ancient subway as cellar storerooms.

Despite a great deal of study not a lot is known about who originally built the tunnels and how they were used in the following centuries. Determing when the tunnels were  built has proved problematic because the mainstay of archaeological dating depends on sifting through different strata.  The prevailing theory is that the tunnels were started by the Hittites sometime between the 11th and 16th century B.C.  Written records are scarce but there are references to a mythical underground city in the Avesta – the early scripture of the Zoroastrian religion dating from the 14th century B.C.

Ahura Mazda advises Yima to construct a Vara (Avestan: enclosure) in the form of a multi-level cavern underground, two miles (3 km) long and two miles (3 km) wide. This he is to populate with the fittest of men and women; and with two of every animal, bird and plant; and supply with food and water gathered the previous summer. Yima creates the Vara by crushing the earth with a stamp of his foot, and kneading it into shape as a potter does clay. He creates streets and buildings, and brings nearly two thousand people to live therein. He creates artificial light, and finally seals the Vara with a golden ring.

A proper historical record of the cave systems begins to emerge sometime in the first few centuries A.D.  From wikipedia:

The city at Derinkuyu was fully formed in the Byzantine era, when it was heavily used as protection from Muslim Arabs during the Arab–Byzantine wars (780-1180). The city was connected with other underground cities through miles of tunnels. Some artifacts discovered in these underground settlements belong to the Middle Byzantine Period, between the 5th and the 10th centuries A.D. These cities continued to be used by the Christian natives as protection from the Mongolian incursions of Timur in the 14th century.

For most of human history individual states have been vulnerable to attack from their their immediate neighbours or the sudden invasion of nomadic groups from far afield.  Some invasions constituted land grabs by empires looking to bring more more people into their sphere of influence but many more conflicts resulted from a simple desire to ransack profitable but lightly defended communities.  Nomadic societies had no need for slaves and rarely had a mechanism for collecting tribute from regions that they conquered so, on many occasions, the victors simply slaughtered those on the losing side.  It’s estimated that Timur’s campaigns across India and Central Asia alone resulted in the deaths of approximately 17 million people (a sizeable percentage of the global population at the time).

In his history of Baghdad historian Edwin Black recounts Timur’s campaigns in apocalyptic terms:

Timur continued his conquests in various directions, almost always dispensing with either hegemony or tribute, preferring instead the incessant delivery of unrestrained torment and death. Only select artisans survived, and these were returned to his camp at the majestic garden city at Samarkand in Persia. There they constructed a magnificent city attesting to Timur’s glory. However those deemed useless were never spared. When he encountered Christian Armenians in the Anatolia region of modern Turkey, the garrison sent children out to sing a song of peace; Timur’s cavalry simply galloped over them. Later he buried the soldiers alive in the city’s moat. In Damascus he massacred the men relentlessly; the mothers were abducted as slaves, leaving their infants to die unattended.

Given the stakes in these conflicts it’s hardly surprising that so many settled societies decided to spend such a large amount of their wealth and their labour force in the construction of defences.  In Anatolia, and all around the Mediterranean, the countryside is dotted with the ruins of walls and fortresses and the remains of earthworks designed to provide refuge in times of war. But those surface structures have always stood as a challenge to invading forces.  Cave systems like those in Cappadocia offer a number of unique advantages.

Unlike a fortress a cave system makes it difficult for hostile forces to determine the number of people who have taken refuge and the provisions available to them. Tunnel systems like Derinkuyu incorporated multiple entrances and several levels that could be independently sealed.  Communications tunnels provided contact with distant settlements. On the surface gates and walls are vulnerable to siege weapons and fire, the tunnels of Cappadocia are difficult to find, let alone access.  The deepest levels of the cave are roughly 85 meters below the surface. Different levels of the cave were separated by giant boulders resembling mill-stones that weighed between 200 and 500 kilograms. These boulders could be rolled out to block passages. A shallow trench prevented the boulder from being levered aside from the outside while narrow passageways would force the attackers to move in single file. Ante-chambers built alongside the entrances included narrow apertures from which defenders could fire arrows or use spears to discourage attackers.   Given the difficulties in fighting underground the more common scenario would have been a lengthy siege- a fact the tunnel builders were well aware of.  Most of these hidden cities had large storage areas and internal wells separate from those accessible from the surface to prevent contamination by attackers. Likewise ventilation tunnels could be scattered across a wide area and camouflaged on the surface.

But it’s hard to imagine that the strategic benefits of these caves would have compensated for the ordeal of life underground.  Light sources would have been scarce and animals and people would likely have been crammed in for days or weeks at a time with no idea what had happened to their homes and livestock and those that remained on the surface.  The stress of living in close quarters, with a reduced diet, vitamin deficiencies and difficulties managing sewage a would have made for very unpleasant conditions and helped spread disease.

Recent studies into the mental health effects of living underground sit within a discipline known as ‘confined environment psychology’.  Informally these conditions are referred to as ‘cabin fever’ and the symptoms are similar to those caused by social isolation, including depression, anxiety and cognitive impairment.  Research has depended on documenting the experiences of prisoners in solitary confinement, scientists living for long periods of time in relative isolation (in polar or arctic regions) and, on some occasions, observation of small groups living in closed-loop environments (such as The US Biosphere 2 and Russian BIOS-3).  There’s been a renewed interest in this area of psychology (and related conditions like seasonal affective disorder) as various organisations begin planning for long-distance space exploration and the potential for permanent colonies on other planets.

What’s missing from this research is data from communities that have successfully adapted to those sorts of environments over a long period of time.  There’s some evidence to suggest that cave cities like Derinkuyu were not just bunkers but homes.  Travelers that passed through the region in the Byzantine era referred to the inhabitants as troglodytes and indicated that they lived in the caves on a more-or-less permanent basis.  If those accounts are to be believed then Cappadocia’s caves could help us understand how a community might adapt-to and even thrive in an underground city.
 
Edwin Black: Banking on Baghdad
Mohammad Ballan: The Scholar and the Sultan
Geoff Manaugh: Derinkuyu or; the allure of the underground city
James Darmesteter: Translation of the Avesta
Lisa Ruth Rand: Biosphere 2

Update: Another underground cave system has been discovered under the township of Neveshir that may be even larger than the complex at Derinkuyu.