There's an old indoor swimming pool hidden directly underneath the White House Press Briefing Room.

Go take a picture with the inventor of the daguerreotype photographic process.

This nine-story building is the oldest standing skyscraper in D.C.

A brass plaque dedicated to a convicted cannibal hangs in the National Press Club, and that's not even the craziest part of the story.

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

An unassuming, powerful monument north of the U.S. Capitol bears witness to the resilience of Japanese Americans during a time of grave injustice.

The privately owned cemetery that holds room for Washington's finest when they step down from life.

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

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

A much-maligned monument to teetotalism.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

One of the most influential presidents in U.S. history wanted only this plain, elegant monument as his lasting memorial.

The grand marble structure next to the White House is Andrew Carnegie's temple to Pan-American diplomacy.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

Corn-inthian columns with a uniquely American take on neoclassical architecture.

The elevator that makes it possible to fly American flags in bulk over the U.S. Capitol

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

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

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

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

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.