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

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

This robust fence in front of a historic Georgetown home is likely made from hundreds of recycled Revolutionary War firearms.

The discovery site of the "Capitalsaurus," the official dinosaur of Washington, D.C.

The institution is sitting on a goldmine of 21,000 paints, varnishes, pigments, and primers preserved for posterity.

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

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

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

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

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

This unacceptably tall building was the real reason for Washington, D.C.'s skyscraper ban.

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

The span is crooked and made from two older recycled bridges.

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

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

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

This lovely pocket park is one of the most under appreciated in D.C.

Need a hardcopy of the 50-title Code of Federal Regulations? This is the place.

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

The oldest continuously operating fish market in the United States.

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

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

100 years later, they're still down there.

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