The mummified heart of Louis XVII, the lost dauphin of the French Revolution.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

France's most famous cemetery, with some of its most curious tombs.

Abandoned railway line circling the city of Paris.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

These medieval skyscrapers dominate the skyline of this small Tuscan town.

Five candy-colored villages on the Italian Riviera.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

Double spiral staircases are not unheard of, but they are very rare.

Op-art architecture designed for happiness.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

This Slovakian statue of an emerging sewer worker might just be a bronze peeping tom.

One of the largest remaining ancient burial mounds of the 10th century.

A collection of items from a way of life that no longer exists.

This modern museum of Mediterranean culture is surrounded by a surreal concrete honeycomb.

Sky ships, planes, and portraits left as unique tokens of hope and thankfulness.

What if all public housing projects had been designed by "the Pygmalion of modern architecture," not only their prototype?

The deepest metro station in the world.

A reconstructed medieval gateway that was the magnificent entrance to the capital city dating back to 1037.

When you've got to go, you've got to go.