A Mars simulation in the southern Utah desert.

The abandoned train depot now doubles as a well-placed rest stop for those who take the road less traveled.

A pair of large white marble lions guard this stretch of the Mojave Desert, and it is utterly mysterious how they got there.

Don't blink or you'll miss it.

The fifth-longest natural arch in the world, and the longest outside China.

All of the 20 occupied houses in this mostly abandoned town feature some curious display of junk art.

A secret fresh water spring for animals and humans alike hidden along the most famous road in the United States.

The first American department store, and home to the largest operating musical instrument in the world.

One of the few surviving "Wigwam"-themed motels.

The drama of nature in full effect in this Nevada State Park.

Neon signs that grace the windows of Bergdorf Goodman's and Tiffany & Co. come from this studio in Brooklyn.

The 340-year-old house that inspired the classic Nathaniel Hawthorne novel.

A storefront museum in Asbury Park honoring the Jersey Shore’s deep history of mystery—including the Jersey Devil.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

The ghost town that ended up on Ebay.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

Ride the subways of yesteryear.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

The world's longest known cave system.

A beautiful geyser under environmental threat.

Elevated freight railway turned wildly successful urban park.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

The only structure left with direct ties to the Salem witchcraft trials of 1692.