This fortress was designed to prevent a Nazi invasion but was never used.

This Stone Age solar temple aligns with the sun on each equinox and solstice.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

Ancient mysterious ruts carved in the bedrock.

The fishing boats that moor in this small lagoon enter and leave through a tunnel to the sea.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."

A futuristic, brutalist masterpiece that is also strangely prison-like.

Two distorted Romanesque columns hold aloft a mine cart in honor of laborers who died during WWII.

A 11-foot former president stands on a Kosovo street that also bears his name.

This fortress dates back to the 6th century and is also the site of a controversial abandoned restoration project.

This 3,800-year-old site contains markers used to study the movement of the sun and moon and create a lunar calendar.

Resonant stone, that has been played since prehistoric times.

Home to nearly a third of the world's mud volcanoes, Azerbaijan is home to a messy, bubbling, and sometimes explosive landscape.

A shrine of fire worship built on top of a natural flame.

Mysterious hillside with a continuously burning natural fire.

This abandoned Greek island was the last active leper colony in Europe.

According to myth, Zeus himself was hidden in this cave to escape being eaten by his dad.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

The oldest olive tree in Greece has been bearing fruit for at least 2,000 years.

These mechanical goats first battled it out in the year 1551, all because of an overcooked deer.

An abandoned football stadium with a tragic past.

An impressive monument to Poland's independence.

A cluster of headless, armless sculptures looms within a popular Polish park.

One of only two places in the world where two rivers cross each other without the waters mixing.