Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.

Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

A 200-year-old bar in the historic French Quarter refuses to give up its place in history, nor its role in securing ours.

Elevated freight railway turned wildly successful urban park.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

This upscale streetwear store is hidden behind a fake Snapple machine in the back of a deli.

A museum dedicated to the history and exploration of both popular music and science fiction.

A Gothic-style abode built to accommodate the church's three resident peacocks.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

A pair of giant legs paying homage to a poem, a king, and it would seem, socks.

The Grand Canyon of Texas.

A wacky, UFO-shaped house in a suburban neighborhood.

This Texas windmill field celebrates the power and majesty of the very winds that blow.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

This backwater graveyard in the Hamptons became a trendy burial spot and posthumous status symbol for famous artists.

The famous winding walk at Chartres is surrounded in mystery and myth.

César Baldaccini's iconic sculpture of a 40-foot thumb stands tall in La Défense.

The mummified heart of Louis XVII, the lost dauphin of the French Revolution.

Former hunting lodge of a duke who was an avid collector of impressionist works.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

France's most famous cemetery, with some of its most curious tombs.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.