Sip creative cocktails in the former vault of the Riggs Bank.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

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

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

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

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

Obscure Freemasons still live in D.C.’s largest private residence.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

Largest Roman Catholic church in North America.

When it opened during the final years of the embargo, all the drinks and cigars were free.

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

The longest-covered bridge in the state of Maryland.

This propitious plastic porcine has been petitioning park visitors to pick up after themselves for more than 50 years.

One of the oldest standing structures in Montgomery County, Maryland.

This 16-foot, intricately detailed model of the Gearing-class destroyer has been called the most detailed model ship ever built.

Unannounced visitors are now welcome at the site of the largest Prohibition-era bootlegging operation in the region.

The headquarters of the Audubon Naturalist Society is a small slice of heaven for nature lovers.

A total of 14 men held the title of "president" before George Washington—their historical legacies are enshrined in the lobby of a hotel.

Three abandoned missile silos are hiding in plain sight behind a suburban development in Maryland.