This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

Eco-village hidden in the foothills of the Alps that created a massive system of psychedelic underground temples.

Centuries-old bridges grown from tangled roots.

This "floating island" plateau sits 7,671 feet above the forest floor.

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

A 19th century artistocrat's mansion, turned into a library, hidden in a modern library.

This "floating railway" is one of the world's oldest monorail systems.

The remains of diamond fever taken over by the desert.

This odd Chilean waterfall-cano hotel must be entered via a rope bridge.

Enormous array of antennae fill a desert valley.

World's largest film studio, where visitors tour the decaying sets that litter the harsh desert environment.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

An architectural marvel that spans the Arda River, and has stories of a haunted past.

World's oldest and largest space launch facility, once a secret missile testing site.

This awesome Spanish castle is so fantastical it was actually used on Game of Thrones.

Cold storage for agricultural biodiversity.

The atmospheric road was never meant to be so creepy.

Turnip-shaped island just off the Michigan shore in Lake Huron.

This stunning Brazilian library contains the largest collection of Portuguese texts outside of Portugal itself.

Hidden in a secluded Greek cove is a pristine beach marred only by the rusting smuggler's hulk stranded on its shores.

A gravity-defying "devil's bridge" that has a surprising architectural feature for its stability.

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

Moss and stone turn this waterfall into an otherworldly liquid veil.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.