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

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

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

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

A flourishing garden with pigs, donkeys, goats, rabbits, guinea pigs, chickens, ducks, and sheep.

Pop culture has helped to keep this iconic British building from being destroyed.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

An artistic tribute to the famous singer, just around the corner from where he was born.

A vast overgrown cemetery, once known as one of London's "Magnificent Seven."

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

The first geometric self-supporting spiral stairs in Britain are a truly beautiful sight.

A historic arboretum and non-conformist, non-denominational park cemetery.

You can still see bits of the camouflage used to hide this Art Deco building from bombers during World War II.

A kaleidoscopic warehouse-maze of handmade neon signs.

One of London's oldest houses contains a mixture of both old and modern features.

Though it's not the largest, this one-kilometer outdoor market is reportedly the longest in Europe.

Originally slated to become a luxurious resort, this structure is now a graffiti haunt reclaimed by nature.

The abandoned club hides in the hills of Ibiza.

The site of the first battle of World War II.

This antique thermometer honors the creator of the first universal temperature scale.