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.

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

Washington's top-secret Cold War-era doomsday communications tower is located in a small neighborhood park.

These abandoned waterworks are crumbling into the Potomac River.

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

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

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

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

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

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

Behind an abandoned storefront is an example of pioneering 1930s gas station architecture.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

A building shaped like the Army Corps of Engineers logo, because why not?

This forgotten boat elevator was an engineering marvel in its heyday.

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

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

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

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

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

Perhaps the most scandalous statue of America's first president.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

Obscure Freemasons still live in D.C.’s largest private residence.