Ancient ruins hidden underneath a modern luxury hotel.

The "Great Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

No monkeying around, this fountain was really named after the classic sci-fi film.

The former estate of the Guggenheims, part of the opulent Gold Coast that inspired the Great Gatsby.

An eccentric playboy's astounding natural history collection.

The house's confection-like decorations are the result of one man's painstaking work over decades.

A museum devoted entirely to the rattlesnakes and snake-related art.

Home of the International Space Hall of Fame.

In a largely deserted ghost town, a little brick building recalls its history as a gold rush hub and haven for outlaws.

Despite time, colonization, and the brutal New Mexican heat, these Pueblo ruins still stand.

This once-palatial plantation may have been the site where a draft of the Declaration of Independence was written.

This cannonball stands as a reminder of the final act of a fleeting governor amidst a revolution.

A church now sits over the site of one of the worst urban disasters of early 19th-century America.

This shifting North Carolina sand dune is an odd little desert surrounded by oceanic forest life.

Beautiful Gothic-inspired lighthouse stands out among the run-of-the-mill striped fare on Bodies Island.

During World War II, blimps were a key part of the United States' defense against German U-boats—this building could house a dozen of the armed airships.

An 83-foot tall granite obelisk honors the legacy of Dr. King in the heart of Norfolk's Black community.

The Cadillac Ranch for monster truck aficionados.

This extensive display of bobbleheads is a tribute to one of the most unique pieces of sports memorabilia.

This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Ch-Ch-Check out the world's largest hand-painted 3D mural.

This replica of a 16th-century French settlement memorializes one of the earliest attempts at a European settlement in North America.

This hauntingly beautiful stretch of Florida coastline is covered in sun-bleached trees.