This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

The place where houses are born.

The largest ice cave in the world is thought to be the entrance to hell according to Austrian legend.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

A sulfuric martian landscape that looks far better than it smells.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

Pilgrimage site for star-crossed lovers.

An ancient Egyptian temple in the middle of Madrid, Spain.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

This bridge was constructed from the rubble of the infamous Bastille.

This massive library holds what was once the largest book collection in the world.

The celebrated eyesore created by starry-eyed sweethearts.

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

This modest marker near Notre Dame identifies the very center of Paris.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

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

A Gothic cathedral created from volcanic rocks.

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

The world's oldest known salt mine.

Between Neo-Pagans and Neo-Nazis, these strange rock formations have a curious cult following and a very strange history.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

This Dresden church was purposely rebuilt Protestant after being demolished in World War II.

Medicinal spa created from the mineral-rich runoff of a geothermal power plant

This natural Icelandic fissure allows divers to swim right between two volatile tectonic plates.