Literal "money laundering."

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

An 18-mile-long tunnel for sewage waste will soon wind within the bowels of Washington, D.C.

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

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

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

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

An overlooked oasis of quiet on the grounds of Washington's monumental basilica.

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

Home to items never before seen by the public.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

"Iron Age" creatures fill this huckster's rusted metal sculpture garden.

A piece of outsider public art accompanied by a strange urban legend.

The uniquely-designed winter home and sculpture studio of Anna and Archer Huntington.

"Not too many people can say they've had a nuclear bomb dropped on them, not too many would want to." — Walter Gregg.

A mailbox that saved a nature reserve.

A mass grave for victims of one of the city’s worst fires.