The bizarre visions of H.R. Giger, tucked away in a Swiss medieval city.

A series of modernist treehouse hotel rooms grace the outskirts of an Arctic forest.

It houses the remains of a 17th-century version of the Titanic.

Sweden's first nuclear reactor, R1, can be visited 25 meters underground.

The best-preserved example of a unique structure in Nubian architecture.

These pillars are one of the few remnants from the mysterious lost empire of Makuria.

Crumbling pyramids and temple ruins stand within the shadow of this sacred butte.

These Nubian pyramids are strange and unique, even by pyramid standards.

The remains of a 37,000-year-old prehistoric society were discovered in this mammoth cave, one of the largest in Asia.

Once thought to be the Garden of Eden it holds a holy footprint claimed to belong to Adam, Buddha and Shiva.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

This African beach is home to thousands of rare mainland penguins that are known for their annoying voice.

Raging waters have created a strange geological site that looks like something off of a progressive rock album cover.

This cave located in the badlands of Somaliland contains some of the oldest cave art in Africa.

The ship that got left behind.

Martin Bricelj Baraga's monolithic sculpture measures the blueness of the sky, and changes color to match it.

A whimsical bridge adorned with decorative dragons.

This one-time health resort was used by aristocrats around the world.

This massive subterranean fissure is known as the "underground Grand Canyon."

Inside the Šomoška National Nature Reserve exists a unique rock formation rarely seen in the world.

This rare wildlife haven in Singapore feels like you're in the tropical rainforest.

This $62 million dollar temple was erected to house one little dental fragment of religious history.

The largest pool at its elevation sits on top of one of the most expensive resorts in the world.