This nondescript building hides an entrance to an underground nuclear tunnel system.

Have a seat with the father of modern computing at this Manchester monument.

A Victorian Gothic masterpiece housing a world-class collection of rare books and manuscripts.

An eerie, derelict amusement park in Berlin.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

This museum is housed in an unassuming building that witnessed one of the most daring feats of satire in modern history.

Christ's blood preserved in a Belgian town.

This communist behemoth is the heaviest building in the world and a legacy of a brutal regime.

Romania's triumphal arch looks out over Bucharest.

This floating sculpture of ice is a poignant reminder of nature's power.

Housing the famous Norwegian ice-defying 19th century polar exploration ship.

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

Across the Pacific in a raft, a museum dedicated to Thor Heyerdahl's now legendary expedition.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

Home to three historic ships from the age of Vikings.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

This subterranean necropolis holds three floors of antler-dug grave caves.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

Climb around the high waterfalls on series of iron ladders and bridges within the wildest gorge in the Slovak Paradise.

The "dragon babies" of southeastern Europe.

A miniature train-ride through Slovenia's largest cave system.

This one-time health resort was used by aristocrats around the world.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

Just another terrifying garden filled with hundreds of endlessly smiling doll people.