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

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

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

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

This massive swimming pool is the high tech home to the human-powered submarine races.

The bridge's highly-contested plaque (once again) honors Confederate President Jefferson Davis.

Every drop of D.C. tap water flows through this old waterworks.

These abandoned waterworks are crumbling into the Potomac River.

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

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

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

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

A 90-year-old underground water reservoir offers a more industrial kind of tranquility.

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

A derelict bit of transportation infrastructure hidden in the woods.

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

This forgotten boat elevator was an engineering marvel in its heyday.

An extensive, if one-sided, history of U.S. law enforcement's war on drugs.

The national park was once a plantation estate.

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

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

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

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

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