Cappadocia's underground cities first began to be chiseled out of the ground in the Bronze Age Hittite era, but they are most famous for their early Byzantine history (6th and 7th centuries), when the region's Christians took to living underground for long periods to escape from Arab and Persian invaders.
Kaymakli Underground City is Cappadocia's largest example, with a labyrinth of rooms connected by tunnels that extends for eight levels. Four of these levels can be explored by visitors.
