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

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

Statue of Lenin, from Cold War era Czechoslovakia, now in a neighborhood of Seattle.

A giant Troll lurks under one of Seattle's oldest bridges.

A wall of chewing gum moonlights as collective art.

A museum dedicated to the history and exploration of both popular music and science fiction.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

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

An eerie, derelict amusement park in Berlin.

The most visited, and possibly most controversial, museum in Germany.

19th century museum with an eclectic mix of curiosities, from Egyptian artifacts to items on archery history to the skull of the world's oldest horse.

Dating back almost 400 years, the oldest public collection library in the United Kingdom was once the study hall of Karl Marx.

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

Repository for more than 22 million pickled specimens.

The curios of pharmacist and collector Henry Wellcome.

The anatomical-pathological collection of a man who changed surgery.

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

This museum houses an imposing skeleton army comprised of creatures great and small.

The first green space constructed on an elevated viaduct.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

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

Digger attempting to hide itself under 300 tons of rubble.

The original home of the Lego has a huge amusement park dedicated to the iconic plastic toy.