Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

These sub-farmland caves are home to a majestic stalactite known as the "Crystal King."

The world's longest known cave system.

Bizarre Cavern.

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

14th century Norse artifacts in Northwestern Minnesota could have proved a Viking landing before Columbus.

America's largest viking stands in a Minnesota city that believes it was visited by the ancient nords.

This replica small town lets visitors take a stroll through the story of progress in the U.S. via thousands of Americana artifacts.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

Thanks to a quirk of elevation this gift shop produces magic doughnuts that are found nowhere else on Earth.

When ecosystems collide in the arid Southwest.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Come for the speed, leave in love with the desert.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

The largest wooden building in the world now houses a fascinating collection of aircraft.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.

Once connected to the outside world by a single train track, this ghost town is looked after by the National Park Service.

A historic coal mine that doubles as a museum and tourist attraction.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.

One of the only memorials dedicated to journalists who died in combat.

Captain John Smith thought these cliffs were amazing in 1608 but sharks thought so 20 million years before him.

The land is home to swimming ponies and a legendary 18th-century treasure.

Nine of the very few concrete ships ever made in the U.S. are beautifully decaying off a Virginia pier.