With over 10,000 lights, this engineering marvel lights up the city after dark.

Fortified homes of highland warriors that are still in use today.

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

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

The charmingly disheveled clock tower of Tbilisi's puppet theater.

Underground monastery and fortress.

Elevated freight railway turned wildly successful urban park.

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

The vibrant buildings in the “capital of the comic strip” celebrate the art form that made it famous.

The largest underground church in Europe.

This medieval village clings to a cliff in southwestern France.

This impressive chasm is one of the longest natural underground cavities in the world.

A 14th century bridge built as a fortress, where the devil lurks on one of its towers.

A medieval church with largest and oldest collection of Renaissance frescoes in France.

Historic medieval fortified city in southwest France.

Immortalized by artists, this church incorporates a medieval lighthouse into its shoreside structure.

This saucy statue once caused outrage among locals.

Napoleon's childhood home is now open for people to explore the beginnings of France's short general.

Abandoned railway line circling the city of Paris.

Notorious artist squat renovated into legal studios.

This isolated island is often capped by its own fluffy cloud.

This isolated and westernmost point of the Faroe Islands archipelago is home to thousands of seabirds.

During the Soviet era, the spire of this longstanding church was used as a radio transmission tower.

Mysterious craters may have been home to an ancient cult.