Turkey’s underground city of 20k people(bbc.com)
bbc.com
Turkey’s underground city of 20k people
https://www.bbc.com/travel/article/20220810-derinkuyu-turkeys-underground-city-of-20000-people
https://www.bbc.com/travel/article/20220810-derinkuyu-turkeys-underground-city-of-20000-people
or more realistically, to hide from violent sieges on the city