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

Site of a classic 19th-century physics experiment to prove the earth is rotating.

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

Single runway interrupted by a busy road that cuts across its middle.

Founded as a refugee camp, now a popular tourist spot.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

Traditional 11th-century outdoor tannery.

Fortune tellers, snake charmers, poets, and storytellers all gather on this historic square in Morocco.

One of the most spectacular canyons in the world.

God's Saharan sandbox of wrath.

The most biologically diverse protected area in Africa is also the most dangerous.

A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.

This famous archeological mystery may be an ancient example of movable type.

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

Every spring, locals see the shadowy figures of a ghost army of slain Greek soldiers descend upon this ruined fort.

This ancient statue of Dionysus lies unfinished and abandoned in one of Greece's oldest quarries.

A model memorial to the original Odin Tower, the second highest tower in Europe before it was sabotaged by Danish Nazis.

An exhibition of preserved locomotives housed in a 1950s depot shows the history of Denmark's railway.

Danish observation tower designed to look like a giant beer bottle.

Denmark's famous pseudo-hill.

Tiring of digging out the door to this church for every service, it was eventually abandoned to the sands.

The original home of the Lego has a huge amusement park dedicated to the iconic plastic toy.

An abandoned lighthouse awaits its destiny: being buried under shifting sand.

The oldest amusement park in the world has been providing a nice spot to have some fun since the 1500s.