The site of an early Arthurian battle and the dwelling-place of prehistoric people and (possibly) an ancient race of giants.

This tumultuous Icelandic lava field looks so alien European researchers want to use it as a stand-in for Mars.

A little-visited waterfall in an otherworldly landscape.

Two volcanic lakes in an enormous crater formed in a prehistoric eruption.

The bright red stripes streaking across the rocks are the star feature at this Icelandic waterfall.

This canyon is comprised of gorgeous waters and magnificent basalt columns.

A little-known, yet charming glacial lagoon.

Climbing Iceland's highest peak on the rim of the Oræfajökull volcano.

What was once believed to be a church floor turned out to be the artwork of geology.

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

A winding, blood-red tunnel of hardened lava navigable by foot.

A hidden slot canyon in the southern Nevada desert makes an unexpected oasis and scenic hike.

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

Train tunnel running underneath Quebec City.

How did the front of a supersonic jet make its way to a display case in a Kansas City yard?

One of Philadelphia's largest murals resides hidden under this bridge.

Mural made of 100,000 pieces of hand blown glass, and until recently, the largest glass mural in the US.

The haunting ruins of Jack London's dream house.

The unedited photograph called "Bliss" has graced the screens of over a billion computers.

A familiar otherworldly creature guards this 12th-century Scottish abbey.

This sinkhole in the Arizona desert is filled with carbonated, arsenic-rich water

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

America's smallest town is run by its single citizen/mayor/librarian/bartender.

According to legend, King Arthur killed a beast that dwelled beneath the waters of this Welsh lake.