One of the oldest used bookstores in the U.S. has been selling antiquarian treasures since 1825.

This failed condo development was reborn as a street art hub.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

Part of a WWII submarine is lurking outside the Washington Navy Yard parking lot.

This grisly headstone doesn’t seem to be resting in peace.

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

A secret greenspace hides atop a Capitol parking garage.

Through the decades, Black music stars have performed at this historic hub for music and the arts.

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

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

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.

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

This unique museum cafeteria showcases the history and regional diversity of African American cuisine.

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

Look closely and you’ll notice that the color changes a third of the way up the tower.

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.

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

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.