Historic barracks utilized during both the Revolutionary War and the Civil War.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

A wondrous old library overlooking the nation's capital.

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

A surprising, but overlooked example of geology in the middle of the nation’s capital.

A derelict bit of transportation infrastructure hidden in the woods.

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

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

Live data is transmitted from the Atlantic coast to instantly recreate the ocean waves in this fountain at the NOAA headquarters.

The wooded estate of the Forest Service employee responsible for D.C.’s cherry blossom trees.

This suburban house is made of dirt, and almost sparked a revolution in home construction.

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

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

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

This suburban park recalls the history of a famous tavern. Despite the name, it's no ordinary place!

The final resting place of the tragic king and queen of the Jazz Age is tucked away in a small Maryland graveyard.

The ruins of an old mill lie in a small ravine along a hiking trail near Little Seneca Creek.

A collection of artifacts from two worldwide industries that called Endicott, NY home.

The hidden ruins of a mill that is linked to an attempt to assassinate the vice president of the United States.

Three abandoned missile silos are hiding in plain sight behind a suburban development in Maryland.