Deadly scalding and one of the largest hot springs in the world.

This electric green sulphur lake in New Zealand looks like a cartoonish radioactive dump site.

The largest natural travertine bridge in the world is nestled in a small canyon in central Arizona.

This beautiful system of tunnels built into natural rock serves as a centuries old plumbing system.

Home to secret Eastern Bloc spy equipment and the largest stretch of the original Berlin Wall outside of Germany.

These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

An unusual house built using an iso-elastic membrane.

This Vietnamese hell cave lets visitors take a walk through a devilish underworld full of demons.

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

These delicate sand pyramids look like naturally occurring gothic spires.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

A naturally occurring tunnel in this Nordic mountain makes it look like it's been shot.

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

A unique attraction and museum dedicated to exploring iconic roadside structures.

This extensive collection of dead bugs may be the world's most idiosyncratic and personal insect museum.

This German version of Universal Studios holds a vault of treasures from the NeverEnding Story.

The world's greatest slide descends 18 stories from this looping mountaintop viewing platform.

Once a menacing challenge for trailblazers, this trail is now the most scenic drive in Utah.

An alien landscape on the banks of the Aegean Sea.

Tiring of digging out the door to this church for every service, it was eventually abandoned to the sands.

Antiques shop filled with all manner of curious collectibles.

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

This massive underground salt mine now holds a sci-fi theme park in its depths.

Stunning examples of Russia's 18th-century wooden architecture.