The famous abolitionist’s preserved estate is one of Washington's finest monuments to its great Black citizens.

An obscure public service from the U.S. government that redeems burnt, moldy, and soiled old greenbacks.

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

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

The walls of the iconic dome are hollow and have a secret stairway.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

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

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

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

A wondrous old library overlooking the nation's capital.

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