A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

At one of Berlin’s oldest churches, visitors can place mosaic tiles to help restore a medieval mural.

The world's oldest known salt mine.

This fairytale medieval church in Poland originally spent centuries in Norway.

Countless grotesque faces stare out from this eerie Prague art wall.

A Jenga-style cylindrical tower of books that appears to go on forever.

This doorless 20th-century elevator doesn't stop or slow down.

A 400-year-old mummified arm dangles from the ceiling of St. James the Greater, serving as a warning to thieves.

Throughout this shopping mall are medieval ruins that were discovered during the mall's construction.

This artificial cave looks like something out of a fairytale.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

This automated sculpture of two men peeing will spell out text messages with their micturition.

The risqué mixed-media sculptures are supposedly a metaphor for Czech politics.

Street artists transformed an abandoned air vent into the beloved Star Wars robot.

Mary Kelly was last seen here before she was murdered by Jack the Ripper.

This unassuming alcove in London’s famous Tower Bridge once served to capture, store, and display dead bodies from the River Thames.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

The ritual has been performed uninterrupted for nearly 700 years.

A mysterious pair of mice eating a piece of cheese is London's smallest public sculpture.

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

An unusual ode to the late Irish playwright, complete with a squiggly bust and coffin-shaped bench.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

A faded reminder of what was once a common sight in London during the Blitz.

A traditional American farmhouse plopped in the middle of a Piccadilly courtyard.