This award-winning men's bathroom was just too beautiful to not allow women to see.

The iconic D.C. restaurant where the Cuban Missile Crisis was negotiated, now a Walgreens.

Bar full of oddities, specimens, artifacts and homages to the great dime museums of the past.

This historic boathouse was constructed using salvaged lumber from burned barns.

A striking memorial to the 21 lives lost in an explosion at the Washington Arsenal

An echo chamber with a waterfall wrapped around its base at the Embassy of Canada in Washington, D.C.

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

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.

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

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

A line of blue paint marks the route of the inaugural parade.

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

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

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

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

"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!”

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

A surprising, but overlooked example of geology in the middle of the nation’s capital.

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

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

This unassuming passageway played a key role in one of the most important events in U.S. history.

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

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

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