Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

Outdoor art exhibition made of classic Tetris pieces.

This historic observatory contains the world's oldest refracting lens telescope.

An ancient rock engraving shows Aboriginals used their advanced knowledge of the stars to hunt and gather.

The Victoria-era quarantine station for Sydney.

Come for the flowers, stay for the bats!

Roadside attraction outside of a recycling center.

Australian museum dedicated to human health and lack thereof.

A self-funded cemetery with a long list of inhabitants.

One of Australia's largest secondhand bookstores.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

The Yonaguni Monument, a natural formation or the Japanese Atlantis?

Not one, not two, but three natural bridges remain in this captivating spot post-sinkhole.

China's beehive-shaped pyramids house the remains of a lost kingdom.

Nova reconstruction of the bridge that baffled engineers for years.

A cliff-hanging restaurant.

Enormous burial mounds of ancient emperors.

Humble beginnings for one of the world's most famous scientists.

The remains of a sunken military ship wreck visible through clear water.

The only gulag ever to exist in socialist Yugoslavia.

Island wonderland for communist autocrats.

This inexpensive lodging house was once a prison notorious for its inhumane practices.

Canada's subterranean Cold War museum has doubled as a movie set.

The purported world's shortest international bridge connects a homeowner in Canada to his backyard in New York.