The oldest continuously operating fish market in the United States.

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

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

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

Home to items never before seen by the public.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

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

This campus chapel is Robert E. Lee's final resting place and a topic of debate about the legacy of the Civil War.

The hide of Stonewall Jackson's equine sidekick is on display not far from where the ashes of his bones are buried.

Giftshop catering to cryptozoologists and anyone with a sense of humor.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

Washington's iconic carousel has a nice piece of Civil Rights history.

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

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

A nostalgic bibliographic gem.