Remnants of the most densely packed city in world history, that thrived on anarchy for 30 years.

The vast chamber inside this abandoned cooling tower looks like something out of a sci-fi dystopia.

Arguing within this idyllic, circular volcanic lake is forbidden.

Khmer Rouge's high security prison.

World's largest collection of serial killer artwork and other macabre exhibits.

This once rural mansion now sits in the heart of the city.

Other-worldly rock formations and ancient fossils abound in this unique stretch of Nebraska badlands.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

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

Dramatic river bend surrounds a natural red-rocked pedestal.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

Most-visited and most-photographed slot canyon in the American Southwest.

Rippling sand dunes frozen in the Arizona rock.

A frozen oasis lies beneath the scorching New Mexico desert.

This towering volcanic plug stands out among the dramatic formations that dot this otherworldly desert valley.

This museum started as a collection of Manhattan Projects and continues to add exhibits as they are declassified.

This pseudo-steampunk weapons facility is the world's largest wood and glue structure, and packs quite a wallop.

This volcano rises like a giant anthill from the plains below, with a road spiraling up to the rim.

A blacklight journey through a celestial art exhibit.

Its history includes dinosaur fossils, cattle rustlers, Georgia O'Keeffe, and a mythical giant rattlesnake named Vivaron.

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

The fictional star of "Breaking Bad" is memorialized with a real-life gravestone in his hometown.