Kaymakli Underground City is one of the largest and most accessible underground cities in Cappadocia, carved into soft volcanic rock. Dating back to the Hittite period and expanded during the Byzantine era, it served as a refuge for early Christians escaping persecution. The city spans eight levels, with four open to visitors, featuring narrow tunnels, ventilation shafts, churches, kitchens, storage rooms, and wine cellars. It’s a fascinating glimpse into ancient underground life, engineering, and survival.