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

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.

D.C. once had its own tiny rival to the New York Stock Exchange.

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

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

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

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

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

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

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

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

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

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

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

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

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

Before Nixon, "watergate" meant canals.

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

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

There just so happens to be a court even higher than the U.S Supreme Court: a basketball court in the building itself.

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

The most accurate timepiece in the world.

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