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

The iconic D.C. restaurant where the Cuban Missile Crisis was negotiated, now a Walgreens.

An Industrial Revolution-era public work that purified water using nothing but sand.

A winding district gerrymandered into the shape of a mantis.

Hidden in an ordinary Midtown building is a one-room museum dedicated to the greatest escape artist.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Elevated freight railway turned wildly successful urban park.

New York's oldest magic store.

A terrific purveyor of natural history objects and curios.

A small poultry graveyard in the courtyard of a popular Key West watering hole.

The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.

An allegorical sculpture in Maryland wears the artist’s politics on its trunk.

WWII-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers. .

A museum and shop on Bourbon Street located in the former home of the second Voodoo Queen of New Orleans.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

Washington's iconic carousel has a nice piece of Civil Rights history.

A celebrity from the late Cretaceous period.

There’s a hidden military meme engraved on the World War II Memorial.

The "lovely red Vega" of the legendary record-settling pilot.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

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

The site of the climactic scene from the classic horror film is now a historic landmark.

Home to items never before seen by the public.