Part of a WWII submarine is lurking outside the Washington Navy Yard parking lot.

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

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

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

An overlooked memorial honoring the local Washington residents who died in World War I.

Helen Keller once broke ground on this historic center for the study of technologies to benefit the hearing impaired.

The fountains of the U.S. Navy Memorial are annually salted with water from the Seven Seas as part of a nautical ritual.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

Before founding the American Red Cross, Clara Barton had a tremendous humanitarian impact by locating thousands of missing soldiers.

A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

Look closely and you’ll notice that the color changes a third of the way up the tower.

A heroic pigeon that, through a barrage of gunfire, delivered a message that saved over 100 lives in World War I.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

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

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

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

Senators used to relax in the nearly forgotten marble tubs now hidden in the U.S. Capitol Building's basement.

A fantastic array of trays and cables once whisked books over to the Capitol at 600 feet per minute.

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

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

The "lovely red Vega" of the legendary record-settling pilot.

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

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.