Four bald cypress trees in Lafayette Square, across from the White House, mark the southern edge of a 100,000 year old cypress swamp.

Home to items never before seen by the public.

One of the largest artillery pieces in the world sits in a Washington D.C. parking lot.

The world's oldest soul food restaurant is also one of its best.

The most accurate timepiece in the world.

A super-sized promotional trick that is now a D.C. landmark.

There's a crumbling old mansion inside the Smithsonian National Zoo.

A Civil War fort in the middle of Washington, D.C. has been swallowed by a forest.

The national park was once a plantation estate.

The oldest continuously operating fish market in the United States.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

A derelict bit of transportation infrastructure hidden in the woods.

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

This grand gothic brewery has been pumping out suds for over a hundred years.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

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

The United States Capitol's former columns still stand.

A rugged lava field dotted with molds of the ancient pines that were growing when the volcano erupted.

This perfectly preserved Chinese medicine shop was untouched for decades before being reopened as a museum.

The world's last remaining store of its kind.

An institution that preserves the history of institutionalization.

This abandoned boat sits on a nude beach, is shaped like a UFO, and is covered in graffiti.

100-year-old shipwreck you can walk up to at low tide.

A crumbling hospital from the 1850s on Roosevelt Island.