The ruins of this Thomas-Jefferson-designed mansion have been left to crumble since the Christmas Day they burnt down.

Home to items never before seen by the public.

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

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

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

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

These unusual rooms on wheels are holdovers from the 1960s.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

An overlooked memorial honoring the local Washington residents who died in World War I.

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

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

A superbly preserved example of Georgian residential architecture that was once home to one of the founders of Alexandria, Virginia.

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

The romance of early commercial flight still fills this Art Deco destination.

A former major munitions plant that has been converted into a sprawling art space.

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

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

Parking garage where Bob Woodward met Watergate source "Deep Throat."

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

This train station inspired the name of a 1970's rock band and provided the backdrop for their album cover.

The former home of the man whose radical ideas changed the nation.

A massive, majestic mammal watches over pedestrians from his perch atop a former B.P.O.E. lodge.

This brick-lined pedestrian walkway was once a railway tunnel used during the Civil War.

America's first federal monument.