Vardzia the (Inhabited) Cave City of Georgia

Akhaltsikhe, Georgia Vardzia is a cave city complex near Akhaltsikhe that was built by Queen Tamar in the 12th century to defend against invaders. The result of this endeavor was a massive city-slash-monastery complex containing 13 floors and 6000 apartments (AND 25 wine cellars AND 13 churches) carved out a cliffside (which goes to show that there’s no better motivational tool than self-preservation).