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

The remains of a failed attempt at medieval nerdery are hidden deep in the woods of Virginia.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

This war hero's old shop remembers the fine line between medicine and quackery during the Revolutionary War.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

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

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

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

A Civil War fort in the middle of Washington, D.C. has been swallowed by a forest.

A haunting tribute to pioneering photographer Clover Adams.

The United States Capitol's former columns still stand.

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

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

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

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

Home to items never before seen by the public.

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

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

The most accurate timepiece in the world.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

There's an old indoor swimming pool hidden directly underneath the White House Press Briefing Room.

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

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