The eroded core of an ancient volcano is now accessible by a short hike.

This no man's land slicing through the island is strewn with abandoned relics of another time.

These mid-century motels once housed the workers who built the Glen Canyon Dam.

This spooky statue sits outside a famous Prague theater.

This subterranean studio is filled with fascinating kinetic art.

This striking royal residence is the largest Renaissance-style castle in Scandinavia.

Before serving as James Bond's Casino Royale, this Victorian-era spa catered to the world's elite.

Old ships and machinery fill a historic harbor in the city that's home to Europe's largest port.

The Netherlands' first car tunnel has an unusually rectangular shape.

This medieval castle was painted pink as part of a now-abandoned children's theme park.

This enormous storm barrier is one of the largest moving structures on Earth, with each arm taller than the Washington Monument.

Yup, that's a 330-foot yacht passing over the highway.

This neighborhood of futuristic ball houses looks like an alien settlement in a science fiction film.

Its town washed away centuries ago, this lonely tower by the sea tells the tale of a mermaid and a curse.

It appears as if a man is standing behind this giant airport clock, painting the hands in real time.

Incredible labyrinth of man made caves.

Seven mini rowhouses fill the gap between 54 and 70 Westerstraat.

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

Rich with fauna and flora, nature-lovers can walk across the sea at this UNESCO World Heritage spot.

The bronzed skull of a beheaded traitor was affixed to the city gate in the 17th century.

Cozy basement bar sports an inventory of over 2,000 beers.

This triumphal arch celebrating the Sun King's conquest of Lille is a masterpiece of military architecture.

When the imprisoned pope's remains were finally returned to the Vatican, his heart stayed behind in France.

The tomb of history's greatest potato promoter is surrounded by tubers.