A restaurant and observation deck built in a unique broadcasting antenna.

Beneath the impressive baroque cathedral that rises from the center of Berlin lies the largest collection of Prussian royals in the world.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".

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

The world's only international cryptozoology museum is host to an unrivaled collection of mysterious objects.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

The "Seinfeld" diner.

New York City's smallest piece of private property.

Elevated freight railway turned wildly successful urban park.

Sid Vicious famously punched a hole in the wall of this iconic music venue.

The fifth tallest statue in the United States is a shirtless monument to the oil worker.

The collection is housed in an exquisite mansion that makes you feel like you've been transported to an Italian villa.

An old spiral fire escape dangles above a public courtyard in Midtown Oklahoma City.

Travel through the hidden underbelly of the city in colorful tunnels filled with art and history exhibits.

Collection of skeletal systems from the "world's leading supplier of osteological specimens."

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

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

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

Giant, friendly pelicans in Central London, the most unlikely of places.

Hear the quietest sound from across the dome.

The palace window through which Protestant nobles flung two Catholic regents, thus sparking the Thirty Years' War.

A turn of the century building boasting some of the most beautiful art nouveau architecture in Prague.