Derinkuyu—the first underground city that we visited in Cappadoccia. Amazing, whatever its story is. And there are a number of theories about these vast and numerous underground cities that pre-date Christianity—although they were used by early Christians to hide from persecution and invaders for centuries. It is generally thought that they were dug for whole villages to hide for brief periods of time while invading armies passed through their village or neighborhood. Short stays of days or a couple of weeks, no longer. No one knows for sure (because of cave-ins and safety concerns) but they extend 12-16 floors underground. There are also theories about how some of them are interconnected—going from one village to another but this has not been proven—no connecting tunnels have thus far been found. They were equipped with churches, dining areas, sleeping areas, areas for livestock, wineries, food stores, etc. Workshops included areas for blacksmiths, potteries, etc. Of course this is all speculation but that is what the students of the cities have come up with. Derinkuyu is perhaps the largest of them and is thought to be large enough to have accommodated 10,000 people for a few days until the invaders would have passed. After Christianity became legal as the official religion of Rome in about 300 A.D., the cities gradually were abandoned and forgotten about—until a local resident discovered Derinkuyu in the 1960s when he was digging a basement for the home that he was enlarging.