An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

The childhood home of the Sultan of Swat is just a line drive away from Oriole Park at Camden Yards.

The world's oldest continuously operating airport was founded by the Wright Brothers.

A mine fire has been burning under the deserted town since 1962, but this church is still going strong.

A toxic ghost town sitting atop a massive coal fire.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

This 16-foot, intricately detailed model of the Gearing-class destroyer has been called the most detailed model ship ever built.

Rediscovered after a century, the father of the American Navy was reinterred in something dredged up from Davy Jones’ locker.

Bizarre Cavern.

Two stone columns flank the grand Venice square, but there were supposed to be three.

Go inside to really appreciate this 500-year-old technological masterpiece.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.

The hallucinogenic center of the ancient world.

This legendary city has been a tourist attraction for centuries.

What looks like a simple quaint estate in rural Pennsylvania was in the 18th century home to a small monastic community.

A failed piece of Orientalism has become the proud symbol of a community.

A winding district gerrymandered into the shape of a mantis.

This former asylum for Black Americans is haunted by its history of violence and racism.

A Maryland museum dedicated to Black history, housed in a historic church.

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

Electronic inventions that resulted in products and systems we use every day are on display in this labor-of-love museum.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.