The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

An underground city of salt.

This crumbling medieval basilica once attracted pilgrims by the thousands to collect a miraculous dust that formed above the saint's tomb.

The ancient latrines of the Greeks, in all their public glory.

A charming beach town in Turkey captures all the colors of the rainbow.

Roman ruins top white travertine terraces formed by ancient hot springs.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

The hallucinogenic center of the ancient world.

The Slovenian architect designed many landmarks in the capital city, including his own dream house.

The "dragon babies" of southeastern Europe.

A whimsical bridge adorned with decorative dragons.

A miniature train-ride through Slovenia's largest cave system.

This one-time health resort was used by aristocrats around the world.

This massive subterranean fissure is known as the "underground Grand Canyon."

This military tunnel dates back to World War II and provides visitors with a little wartime adrenaline.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

When a supermarket opened up shop within a medieval building it became protected by UNESCO on a technicality.

A musical instrument played by the sea.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

You may recognize this beautiful grove within Kaitoke Regional Park as location of the house of Elrond.

High winds can make this one scary landing.

Inside this faux cave, visitors can learn how some of their favorite fantasy characters were created.