An alchemist's "magic door" stands in the middle of a Roman park.

A submerged archeological park still holds the wonders of a Roman Sodom.

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

A 16th-century horror show built in a lovely Italian garden.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

This rare basalt crater lake is used to study the Moon and Mars.

Museum preserving torture methods from the past.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

It's said to be one of the most significant collections of contemporary Chinese art in the world.

A haunting exhibit in a wildlife refuge center highlights threatened species and the conservation efforts needed to save them.

Over a million items cram the shelves at Africa's largest shop of used and rare books.

Iran's colorful terraces are a rare geological masterpiece.

Take a walk in a recreation of ancient Rome.

An industrial relic is now one of Europe's most staggering art spaces.

A wunderkammer of mysterious objects and stories.

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

Gardens representing parts of Asia, Europe, and the Mid East are tucked away among the Soviet-style buildings in East Berlin.

Where once there was a train station bathroom, there is now this German burger joint.

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

From toys to kettles to scientific instruments, this German museum celebrates the beauty of 20th century design.

A state-of-the-art medical facility from the Imperial era is now a derelict ruin.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

A slice of central Asia in the middle of Berlin.

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