Before Nixon, "watergate" meant canals.

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

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

There’s a special club house at the top for the bell ringers.

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

The hidden offices underneath Memorial Bridge have been locked up since 1976.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

This lovely pocket park is one of the most under appreciated in D.C.

Cold War intelligence agents monitored communist embassies from an attic in a former pigeon coop.

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

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.

The national park was once a plantation estate.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

Government testing at the asylum briefly explored using marijuana as a "truth serum" on Nazi prisoners of war.

Where the U.S. government kept its actual treasure, before Fort Knox.

Decades before the scandal, this staircase on the river was a literal "water gate."

A historic ruin just 20 feet away from a busy highway onramp.

Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

This sandwich shop has a century-old elevator behind a sheet of plexiglass.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

There's a crumbling old mansion inside the Smithsonian National Zoo.