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

Light bulbs, scrap wood, and tinfoil comprise this homemade throne of the gods.

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

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

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

The institution is sitting on a goldmine of 21,000 paints, varnishes, pigments, and primers preserved for posterity.

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

The span is crooked and made from two older recycled bridges.

Seemingly unremarkable items like empty sushi trays, chef hats, and freshness stickers are being preserved so future generations can look back on this beloved cultural import.

Housing the National Women's Party since 1929, this historic house is now a monument to the fight for gender equality.

Four bald cypress trees in Lafayette Square, across from the White House, mark the southern edge of a 100,000 year old cypress swamp.

A brass plaque dedicated to a convicted cannibal hangs in the National Press Club, and that's not even the craziest part of the story.

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

The most accurate timepiece in the world.

Decades before the scandal, this staircase on the river was a literal "water gate."

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

Home to a vast and influential collection of Shakespeareana.

A super-sized promotional trick that is now a D.C. landmark.

A haunting tribute to pioneering photographer Clover Adams.

Cold War intelligence agents monitored communist embassies from an attic in a former pigeon coop.

The house where John Wilkes Booth conspired with his co-conspirators.