This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

The first island in the world designated a light-pollution-free astronomical observation point.

A surprisingly beautiful abandoned World War II military base in East Greenland.

The hallucinogenic center of the ancient world.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

Underground monastery and fortress.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Rent out a glass igloo to watch the Northern Lights like you live in the future.

This isolated island is often capped by its own fluffy cloud.

"There's nothing there," and other lies the KGB told us.

Copenhagen's celebrated theme park and gardens.

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

A magical museum of fairy tale treasures near Cyprus' buffer zone.

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

An abandoned saucer-shaped monument in the Bulgarian mountains.

There's a mini version of Iguazu Falls hidden in the Balkans, and it's got a rope swing.

Each spring, a dreamlike carpet of bluebells overtakes the forest floor.

Thanks to its heroic service during WWII this Soviet castle has been turned into a monument towered over by a brutalist titan.

A geological oddity topped with a 2,000-year-old pagan temple.

In one of the smallest countries in the world stands an original Salvador Dalí sculpture.

A naturally beautiful, seemingly bottomless deep blue spring.

One man's journey to return a stone to its point of origin after 200,000 years.

A huge, bustling local market in Panama City.

The youngest volcano in Central America.