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

A wondrous old library overlooking the nation's capital.

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

The oldest continuously operating fish market in the United States.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

A building shaped like the Army Corps of Engineers logo, because why not?

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

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

The national park was once a plantation estate.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

Amid the sprawling Defense Intelligence Agency Headquarters is one of Washington's least accessible museums.

The remains of a historic plantation nestled in between a parking lot and the rental car return at Reagan National Airport.

An out-of-place Air Force radar dome is all that denotes this park as a former missile launch site.

An isolated island home to one of the oldest English-speaking communities in the region and Maryland's state dessert.

Captain John Smith thought these cliffs were amazing in 1608 but sharks thought so 20 million years before him.

The narrowest house in America is seven feet of pure spite.

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

An original apothecary from 1792.

A mammoth pair of Civil War artillery guns abandoned out in the forest.

The oldest bridge in South Carolina may have been designed by the same man who created the Washington Monument.

A wedding chapel, vintage clothing shop, and bar all under one roof.

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

This North Carolina museum is keeping the pinball craze alive, with a little Space Invaders on the side.

Every week, a festive public jam session breaks out in downtown Asheville.