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

After millennia of erosion by sand and churning water this Brazilian valley now looks like a lunar fantasy.

A massive natural rock arch gives the Tuscan mountain its own window to the sky.

A long, winding trek rewards you with a gorge so captivating it inspired a painting in the Tate.

An ancient Scottish rock formation said to be the gravesite of a giant remains ensconced in legend and intrigue.

Strange rock formations tower above the river that snakes through this enchanting Icelandic canyon.

Rare recess caves fill this unbelievably beautiful Ohio park.

The land is full of geologic eye candy, such as otherworldly spires, mushroom-shaped hoodoos, and prehistoric fossils.

A fiery crater has been burning in the Karakum Desert since 1971.

The world is full of swimming holes, but few compare to Samoa’s idyllic To Sua ocean trench.

Natural rock water slides hidden in the remote forests of northern Idaho.

Did Inca children also slide down these smooth rocky slopes above Cusco?

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

Four-story slides send people whizzing through the math department at this Munich university.

Why walk on this historical site when you can zoom down instead?

From 135 feet high riders plunge down the world's tallest freestanding body slide at 65 mph.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

A subterranean playground in an abandoned slate mine.

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

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

A swing to dangle you off the very edge.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

Mirrored floors and arched shelves create the illusion of an infinite tunnel of books.

Nestled in Uganda's Semliki Valley Wildlife Reserve, is a one-of-a-kind safari lodge.