It was once the base for a series of domestic terror attacks.

Surrounded by a verdant garden and a backdrop of ivy, a monument to beloved poet Khalil Gibran stands outside of the Lebanese embassy.

On the Fourth of July this area will transform into a Pompeii-like storm of falling embers and ash.

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

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

The U.S. Navy’s preposterously detailed mini battleship took 77,000 hours to complete.

An obscure federal monument honors the French diplomat who served as Ambassador to the U.S. during WWI.

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

A portal into the bricked up canal that runs through the heart of Washington D.C.

A hidden passageway now marks the site of an assassination attempt on Ronald Reagan that some say broke a 140-year-old curse.

The school tested mustard gas for the U.S. Army during World War I.

"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!”

The first memorial dedicated solely to the Black troops who fought for the Union.

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

When it comes to handsignals (and colonialism) rock always beats scissors.

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

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

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

A much-maligned monument to teetotalism.

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

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

One of the largest artillery pieces in the world sits in a Washington D.C. parking lot.

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

Washington's iconic carousel has a nice piece of Civil Rights history.