It's hard to capture in photos, but these caves are cut out of the rock, underground, and can hold ~20,000 people. They lived here for a couple hundred years, hiding in the barren desert. Well, underneath the barren desert. It's pretty insane,and no one knows how big the city is, but it goes down 120 meters and the tunnels go on and on. Houses, churches, grave sites, wells, wineries, you get the picture. Look up underground cities, Turkey in Wikipedia and don't faint. It's amazing.