During the Byzantine period, Christians were persecuted for their religion and built the Cappadocia underground cities. During the Arab-Byzantine Wars between 780 and 1180, the city’s residents utilized the network of caverns for protection from Muslim Arabs.

Naturally, these subterranean cities also served as fortifications, shielding their residents and Cappadocia made provisions for this, including thick doors and even holes in the ceilings through which to pour hot oil on any invaders.