The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

Forget Hollywood, one of the biggest stars in the world can be found in Roanoke, Virginia.

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

This pre-Revolutionary War grist mill ground corn and flour for soldiers in seven American wars.

One street divides a single town that stands in two U.S. states.

At 207 feet, one of the world's longest continuous escalators.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

A secretive collection featuring objects that were designed specifically for U.S. intelligence operations.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

The 28,000-year-old specimen is remarkably intact.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

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

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

Look closely and you’ll notice that the color changes a third of the way up the tower.

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

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

There's an old indoor swimming pool hidden directly underneath the White House Press Briefing Room.

100 years later, they're still down there.

Art deco landmark on the outskirts of Washington, D.C.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.