The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

Look closely and you’ll notice that the color changes a third of the way up the tower.

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

Helen Keller once broke ground on this historic center for the study of technologies to benefit the hearing impaired.

Home to a vast and influential collection of Shakespeareana.

The hidden offices underneath Memorial Bridge have been locked up since 1976.

A derelict bit of transportation infrastructure hidden in the woods.

A wealth of local folk art, antiques, and curios, without ever leaving your car.

Dothan, Alabama has been invaded by scores of anthropomorphic peanuts.

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

Home to items never before seen by the public.

An annual extravaganza of Broadway theater memorabilia.

One of only two commuter aerial tramways in the United States.

Order scoops of pandan, lychee, and black sesame at this family-run institution.

A semi-scholarly approach to sex.

Manhattan's Thirteenth Avenue was made on landfill then deliberately destroyed — apart from one small, obscure block.

The iconic Manhattan corner that was once the site of the Beastie Boys' fake clothing store.

The haunting, dilapidated remains of a former poorhouse on Staten Island's Greenbelt.

The nearly 120-year-old piece of pork wears a brass collar and was once a man's "pet ham."

The ghostly remains of an accidental sea.

Non-profit time travel mart sells goods you would need for a trip through the fourth dimension.

Oldest building in California still in use.

A Norwegian-born sculptor created these soaring guardian angels at the entrance to Hoover Dam.