This forgotten boat elevator was an engineering marvel in its heyday.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

An overlooked tribute to one of the most important peace deals in American history.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

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

A wondrous old library overlooking the nation's capital.

A small token of gratitude from freezing cold journalists who were given a warm haven while covering JFK's inauguration.

Sit where JFK proposed to Jackie or where Nixon dined on meatloaf at this storied pub.

Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

An out-of-place Air Force radar dome is all that denotes this park as a former missile launch site.

A building shaped like the Army Corps of Engineers logo, because why not?

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

Daily lunch spot for many of Washington, D.C.'s cab drivers.

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

A historic arena where the Beatles played their first concert in the U.S.

More than 500 unique and specially designed cases collected by D.C.'s "Harmonica Case Man."

This grand gothic brewery has been pumping out suds for over a hundred years.

The sculptor was instructed to add “stallion attributes” to the general's bronze mare.

This robust fence in front of a historic Georgetown home is likely made from hundreds of recycled Revolutionary War firearms.

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

A small triangle of DC grass is the final resting place of one of Sonny and Cher's songs.

Behind an abandoned storefront is an example of pioneering 1930s gas station architecture.

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

People escaping slavery may have hidden inside a corpse vault.