LARGEST ANCIENT UNDERGROUND CITY HOUSED 20 000 PEOPLE

Can you picture a subterranean metropolis just behind your home's walls? Many of us have fantasised about having a door in our house that opens to a secret realm. A Turkish man discovered the historic 18-story underground city of Derinkuyu in 1963 after tearing down a wall in his basement.

One of the biggest underground towns in the world, Derinkuyu, formerly housed up to 20,000 people. It is one of more than 200 underground cities cut into the volcanic rock in the Cappadocia area of Turkey. In reality, there are kilometres of tunnels connecting Derinkuyu to some of these underground communities. The city's more than 250-foot depth and the organisation required to accommodate a subterranean populace are two factors that contribute to its impressiveness.

The existence of Derinkuyu was made possible by ancient volcanic eruptions. Ash, also known as tuff, accumulated in layers over millions of years and eventually transformed into a sturdy rock that could be cut. Residents of Cappadocia discovered long after the eruptions that they could dig underground and sculpt their homes from the rock.

The Phrygians, an Indo-European people, are believed to have founded the underground city of Derinkuyu between the eighth and seventh centuries BCE. They started adding chapels to their underground homes once the populace converted to Christianity during the Roman era. The underground city is believed to have served as a haven for Christians fleeing Roman persecution. However, the underground city thrived during the Byzantine era. Derinkuyu served as a haven for Muslim Arabs throughout the Arab-Byzantine wars, which lasted from 780 to 1180. It was at this time that the tunnels that connected the underground settlements were constructed.

According to a different version, the underground city was created much earlier by the Anatolian Hittites. Construction began about the 15th century BCE, and the region was used to escape enemy invasions.