Monks in the empyreal Alazani River valley have preserved their 1,000-year-old winemaking tradition.

Italian cave with exceptional acoustics and an unsavory history.

The second largest in the world, this massive underground void has its own subway.

The second-deepest known cave on Earth, hidden in an extremely remote mountain region.

This sacred cave temple is home to thousands of bats and according to legend, a giant snake king.

Along the most northwestern point in Africa is an ancient cave surrounded by legends.

You'll find just about anything in this funky Tbilisi flea market.

A cluster of historic bathhouses built on the famed hot springs that gave the Georgian capital its name.

Legend says these stone structures are where the doomed citizens of a vanished village sent themselves to die.

A centuries-old forgotten underworld lies beneath Malta.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

A 2,000-year-old engineering wonder hides beneath an Italian town.

Take respite inside this jaw-dropping church while climbing the volcano where Georgia's Prometheus was once chained.

The cave holds a spectacular array of stalactites and stalagmites, including one shaped like a giant human heart.

Small church on top of a huge rock column.

Rock-hewn monastery complex with hundreds of cave structures tucked away into the mountainside.

Underground monastery and fortress.

Ancient rock-hewn town that witnessed key events of Georgian history.

A Turkish monastery tucked into a cliff wall.

The second-largest Jewish temple in Bulgaria was deserted after World War II, seized by the communist government and then abandoned again.

A spectacular Bulgarian cave resembling a devil's head with a waterfall rushing down its throat.

An architectural marvel that spans the Arda River, and has stories of a haunted past.

Bizarrely shaped rock formations in northwest Bulgaria come with equally bizarre legends.

The ceiling of Prohodna Cave in northern Bulgaria affords a peek at the sky via two deity-sized-eye-shaped holes.