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

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

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

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

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

Before Nixon, "watergate" meant canals.

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

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

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

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

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

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

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

A historic ruin just 20 feet away from a busy highway onramp.

This poor little statue is the most vandalized memorial in Washington.

The most accurate timepiece in the world.

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

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

Light bulbs, scrap wood, and tinfoil comprise this homemade throne of the gods.

The privately owned cemetery that holds room for Washington's finest when they step down from life.

You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

When it opened during the final years of the embargo, all the drinks and cigars were free.