Cappadocia

It's vast. It's old. There are many caves. Christians used to live in them. Now tourists stay in cave hotels.

Or as the Lonely Planet says:

The Hittites settled Cappadocia from 1800 BC to 1200 BC, after which smaller kingdoms held power. Then came the Persians, followed by the Romans, who established the capital of Caesarea (today’s Kayseri). During the Roman and Byzantine periods, Cappadocia became a refuge for early Christians and, from the 4th to the 11th century, Christianity flourished here; most churches, monasteries and under ground cities date from this period. Later, under Seljuk and Ottoman rule, Christians were treated with tolerance.

Cappadocia progressively lost its importance in Anatolia. Its rich past was all but forgotten until a French priest rediscovered the rock-hewn churches in 1907. The tourist boom in the 1980s kick-started a new era, and now Cappadocia is one of Turkey’s most famous and popular destinations.