It was once the base for a series of domestic terror attacks.

A gift from Japan, 17th-century lantern stands among the cherry trees at D.C.'s Tidal Basin.

One of the three perfect vellum copies of this historic book known to exist is on display in a specially-designed case.

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.

Coins and medals straight from the mint await visitors to this shop in the nation's capital.

The National Park Service’s best-kept secret with views that rival any in D.C.

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

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

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

A heroic pigeon that, through a barrage of gunfire, delivered a message that saved over 100 lives in World War I.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

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

The "lovely red Vega" of the legendary record-settling pilot.

Washington's iconic carousel has a nice piece of Civil Rights history.

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

This unique museum cafeteria showcases the history and regional diversity of African American cuisine.

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

Perhaps the most scandalous statue of America's first president.

The most decorated dog of World War I is preserved in the Smithsonian.