The only surviving 19th-century water-powered mill found in the Washington, D.C. area.

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

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

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

One of the oldest standing structures in Montgomery County, Maryland.

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

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

A rotating cast of guys and dolls in front of a Washington, D.C. building.

America's first federal monument.

Once forgotten and built over, this historic Black cemetery now houses a poignant memorial.

Catch a ride through the Pennsylvania countryside on this historic narrow-gauge railroad.

A memorial to a shareholder activist feared by CEOs around the United States.

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

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

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

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

The rooster who crossed the road lives on forever in Takoma Park, Maryland.

An allegorical sculpture in Maryland wears the artist’s politics on its trunk.

A diminutive plaque recalls the treetop sniper who almost killed Abe Lincoln.

She stares out across six lanes of traffic, clutching a musket and infant with determination.

A benevolent, 16-foot-tall river dragon lives on a suburban lawn.

Built in 1945, this historic train station has a new lease on life with its baggage area serving as an event space.

A tribute to the beloved, kind-hearted "homeless mayor" of Silver Spring.

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