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

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

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

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.

Before Nixon, "watergate" meant canals.

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

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

The oldest continuously operating fish market in the United States.

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

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

The most accurate timepiece in the world.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

A haunting tribute to pioneering photographer Clover Adams.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

Largest Roman Catholic church in North America.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

A nostalgic bibliographic gem.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

Home to items never before seen by the public.

The site of the climactic scene from the classic horror film is now a historic landmark.

The United States Capitol's former columns still stand.