The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

A marvel of Byzantine engineering under the streets of Istanbul.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

A Turkish monastery tucked into a cliff wall.

This neon lit Georgian cave claims to hold the boulder Prometheus was chained to.

Small church on top of a huge rock column.

A huge monument to a bizarre book written by Turkmenistan’s longstanding dictator.

Sumptous memorial to a controversial independence.

If you want to get married in the White Marble City of Ashgabat, you should do it in this surreal disco ball building.

A dictator's gold statue once rotated to face the sun on a 75-meter high marble tower.

A spectacular rainbow of stained glass makes the "Pink Mosque" one of the most beautiful in Iran.

Huge concrete structures designed as an early warning system for Britain to detect enemy aircraft.

A house of bones — but nobody is quite sure to whom they belong.

This circular Iranian jail was once a political prison run by the country's secret police.