A hillbilly theme park that proved so unpopular the land wouldn't even sell on eBay after it closed.

Four-story concrete hotel never opened to customers.

This innocuous New Mexico storefront was once the secret jump-off spot for Manhattan Project scientists.

The site of an underground detonation of a megaton nuclear bomb in the middle of the Mojave Desert.

"Not too many people can say they've had a nuclear bomb dropped on them, not too many would want to." — Walter Gregg.

The largest man-made crater in the U.S. marks the spot where we once tested mining with nukes.

This largely forgotten piece of Cold War history stands hidden in the woods just north of the Mississippi Gulf Coast.

On October 26, 1963, a 12-kiloton nuclear device was detonated here in granite some 1,211 feet below the ground surface.

The site where a nuclear bomb was lowered over 8,000 feet underground and detonated as an experiment in natural gas extraction.

This national park on the shore of Lake Michigan features remarkable dunes that lie at the heart of a Chippewa legend.

This rare example of a "tidefall" is a spectacular drop from the cliffs down onto the beach.

A rare kind of blue bear can be found chiefly in the national park that shares their name.

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

These ruins of a pre-Columbian cliff village are among the most beautiful and well preserved in New Mexico.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

This magical grotto is adorned with a complex pattern of native seashells, minerals, and fragments of colored glass.

This massive underground salt mine now holds a sci-fi theme park in its depths.

The Beaux-Arts aquarium boasts a vast collection of saltwater and freshwater fish on an island in the Detroit River.

Stuck in a bygone era, the oldest subterranean shopping street in Japan hides beneath the popular Asakusa district of Tokyo.

Ute tour guides have been sharing the ancient dwellings and rock art inside this large park with visitors for more than 40 years.

This abandoned island off the Venetian coast has been a radical monastery, a political prison, and a secret Nazi base.

Ruins of a Carnegie family mansion on Cumberland Island.

This Canadian island is a veritable garden of decay with countless abandoned structures dotting the landscape.

This foolish Victorian sea fort was converted to a deluxe hotel.