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

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

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

A hidden passageway now marks the site of an assassination attempt on Ronald Reagan that some say broke a 140-year-old curse.

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

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

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

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

The oldest continuously operating fish market in the United States.

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

The national park was once a plantation estate.

The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

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

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.

Elevated freight railway turned wildly successful urban park.