Abandoned railway line circling the city of Paris.

Notorious artist squat renovated into legal studios.

Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

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

Scores of wax baby figurines add an unusual mood to this beautiful church on the Greek coast.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

The world's biggest floating museum in Gothenburg, Sweden.

A peculiar clock commemorates a historic victory won by ringing the noonday bell an hour early.

This hanging crocodile is thought to be the "dragon" that once plagued a Czech city.

Europe's second largest ossuary wasn't discovered until 2001.

Also known as the Blue Church, the building was consecrated to the daughter of Andrew II.

An unusual cave filled with rare alien-looking aragonite formations.

The 700-year-old fortress was the site of Count Orlok's castle in "Nosferatu."

The bears of Bern have been a city highlight for over 500 years.

Large Hadron Collider and the Birthplace of World Wide Web.

This historic covered bridge contains a series of macabre paintings that communicate one thing: everyone dies.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

Home to three historic ships from the age of Vikings.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

The art museum is decorated with creatively remodeled pre-Nazi swastikas.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

The Guardian of Tallinn.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.