Major tourist destination known for its bubbling mud-pools and hot thermal springs.

Stroll through a wonderland of stupendous moss-covered trees.

Prehistoric park filled with the fossils of dozens of extinct species including Australian megafauna.

This "dead marsh" sits among the largest sand dunes in the world, a forest frozen in time.

Home to nearly a third of the world's mud volcanoes, Azerbaijan is home to a messy, bubbling, and sometimes explosive landscape.

Rippling sand dunes frozen in the Arizona rock.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Towering basalt columns, a creation of fire and ice.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

New fungal and bacterial species call this deadly lake home.

Send a postcard while vacationing with Satan.

An eatery for UFO seekers on the Extraterrestrial Highway.

In the middle of an extremely unforgiving and desolate high desert is the most secret military facility in the world.

Mysterious meeting place for UFO hunters near Area 51.

Are these prehistoric metal pipes evidence of alien plumbers? Nope, but they are amazing nonetheless.

A flooded Mexican cave that hides a river beneath the water.

Sandstone rock formations that look like they belong on the cover of a progressive rock album.

Welded sphere dropped from space.

Wondrous stalactites house thousands of bats in these African caves.

The fossilized remains of ancient California redwoods.

California's own medieval Italian castle, authentic down to the 300-year-old iron maiden in the dungeon.

Smooth basaltic rocks tell a tale of ancient glacial waterfalls.

On a barren hillside in the Yucca Valley, the recently restored Desert Christ Park has attracted pilgrims and kitsch hunters for over 50 years.

A magically clear, blue river that seems to spring from nowhere.