The oldest continuously operating fish market in the United States.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

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

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

A historic neighborhood church is reborn as a psychedelic arts collective.

The first national memorial to honor all women suffragists stands on land where suffragists were once imprisoned.

This rowhouse doubles as one of the most photographed spots in the nation's capital.

Mural made of 100,000 pieces of hand blown glass, and until recently, the largest glass mural in the US.

The revival of a classic Art Deco theater.

The hippo that stands on this university campus was once a drunken flea market purchase.

This small hilltop church weaves the urban history of Washington, D.C. with the national history of the United States.

On the Fourth of July this area will transform into a Pompeii-like storm of falling embers and ash.

The final residence of an educator, civil rights leader, and presidential advisor was also the first headquarters of the National Council of Negro Women.

Outside the Department of Transportation, a collection of artifacts honors the history of how we get around.

The National Park Service’s best-kept secret with views that rival any in D.C.

A replica of the famous memorial statue at the Normandy American Cemetery hides in an office building in downtown D.C.

Once a sewer culvert, this road tunnel now offers cyclists and pedestrians a subterranean stroll under the C&O Canal.

A secret greenspace hides atop a Capitol parking garage.

The word "Watergate" will forever be associated with the infamous scandal in 1972, but this fountain is famous in its own right.

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

The 28,000-year-old specimen is remarkably intact.

Atop this media building, two hives containing more than 30,000 bees keep the surrounding area vibrant.

Where you can hail your favorite fictional commanders-in-chief.

The Wright Tavern is possibly the most important building in Concord Massachusetts to the American Revolution.