This ancient theater was once the home of fierce gladiatorial battles.

This Corsican Neolithic site is full of pre-Roman megalithic structures that may or may not be penises.

The Church of the Annunciation was carved into the face of a cliff, just like the rest of the town of Haute-Isle.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

The world's largest reflecting pool is just two centimeters deep.

Hundreds of prehistoric stones, arranged in perfect lines in a French field.

The largest underground church in Europe.

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

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

Ancient paintings known as the "Sistine Chapel of Cave Art."

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

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

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

A cathedral resurrected from the ashes of one of Europe's greatest urban fires.

An abstract monument to a symphonic composer.

Collection of nearly 500 concrete figures sculpted by the late Veijo Rönkkönen.

A subterranean house of worship carved right out of the bedrock.

A small Denmark town displays a pair of titanic jaw bones as their community symbol.

Mounds, rune stones, and a 1,000-year-old church, left behind by Denmark's first two kings.

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

This Danish castle is supposedly haunted by a woman too independent to not be a witch.

Four alabaster giants contemplate the tides on the shore of Denmark.

The northernmost point in Denmark is a turbulent sandbar created by two clashing seas.

A natural wonder in south Denmark.