Visit a surreal landscape so otherworldly NASA actually used it to train the Apollo 17 crew.

During the 19th century, you could pay for violence off a prix fixe menu on this Manhattan street.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

An abstract monument to a symphonic composer.

Finland's oldest astronomical observatory once played a crucial role in seafaring and timekeeping.

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

An alien church provides much needed silence in the midst of a Finland shopping center.

This medieval Estonian tower provides access to a series of tunnels that have been home to soldiers, punks, and fine art.

The Guardian of Tallinn.

The oldest continuously operating pharmacy in Europe.

"There's nothing there," and other lies the KGB told us.

This no man's land slicing through the island is strewn with abandoned relics of another time.

The sweet story of how American cargo planes became known as "Candy Bombers" during the Berlin Blockade.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Hear the quietest sound from across the dome.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

Banksy's image of a naked man dangling from the window of a sex health clinic.

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

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

Some of the greatest minds in the history of Hungarian art and science converged in this café.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.