This extraordinary geological oddity resembles human-made pavement.

Islanders once used this dramatic, otherworldly landscape to hide their cattle from Viking raiders.

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

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

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

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.

Romania's "Red Ravine" is a little-known natural wonder that bears a resemblance to the Grand Canyon.

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

Climb down into the largest sinkhole in Qatar.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

These layered sandstone mountains in China look like they are made of pressed crayons.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

This vertical pinnacle in China was the inspiration for the floating mountains in the movie “Avatar.”

Ten shipwreck-shaped chalets lie along the sand dunes on Namibia’s Skeleton Coast.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.