A portal into the bricked up canal that runs through the heart of Washington D.C.

A wondrous old library overlooking the nation's capital.

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

They sort through millions of dollars worth of diplomatic gifts on behalf of the government.

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

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

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

For 60 years, the academy had no permanent location until members voted Washington D.C. as its forever home.

The span is crooked and made from two older recycled bridges.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

The oldest continuously operating fish market in the United States.

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

An overlooked memorial honoring the local Washington residents who died in World War I.

A derelict bit of transportation infrastructure hidden in the woods.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

A building shaped like the Army Corps of Engineers logo, because why not?

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

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

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

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

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

The national park was once a plantation estate.

The only National Monument ever to go missing for nearly 50 years then resurface in a dump.

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