This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

This little brick tunnel built by Confederate forces was used to conduct surprise attacks on the railroad.

The ruins of this long-abandoned unsuccessful gold mine can still be found.

Home to a 27 room house, this estate was crafted by Black entrepreneur Olander Banks Sr.

Hidden in the forest atop a long, winding driveway is this stately home.

The local community brought back this land to transform it into a nature preserve.

A mammoth pair of Civil War artillery guns abandoned out in the forest.

This brick-lined pedestrian walkway was once a railway tunnel used during the Civil War.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

A historic cemetery filled with quirky faux wood art and unique tombstones.

An intricately designed junk art house with four extravagant junk art cars hidden in the suburbs.

Government testing at the asylum briefly explored using marijuana as a "truth serum" on Nazi prisoners of war.

Concerned residents saved this historic house and garden from demolition.

Remnants of a wall built to separate Black residents of Hall's Hill from a newly built subdivision are a grim reminder of segregation in 20th-century Virginia.

These abandoned waterworks are crumbling into the Potomac River.

A historic cemetery with unique artwork, a Civil War fort, and also happens to be the site of the Battle of Bladensburg.

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

Washington's top-secret Cold War-era doomsday communications tower is located in a small neighborhood park.

The remains of a historic plantation nestled in between a parking lot and the rental car return at Reagan National Airport.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

The United States Capitol's former columns still stand.

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