Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

The massive machine creates cracking displays of indoor lightning.

This sculpture perfectly models the molecular structure of a drug that was never produced.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

There’s a special club house at the top for the bell ringers.

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

Home to a vast and influential collection of Shakespeareana.

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.

At 207 feet, one of the world's longest continuous escalators.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

This historic boathouse was constructed using salvaged lumber from burned barns.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

The oldest continuously operating fish market in the United States.

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

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

The national park was once a plantation estate.

When it comes to handsignals (and colonialism) rock always beats scissors.

Surrounded by a verdant garden and a backdrop of ivy, a monument to beloved poet Khalil Gibran stands outside of the Lebanese embassy.

Need a hardcopy of the 50-title Code of Federal Regulations? This is the place.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

Decades before the scandal, this staircase on the river was a literal "water gate."

A tribute to the pop culture icon overlooks this Washington D.C. intersection.

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.