The world’s first penitentiary, meant to be humane, drove men insane.

This impeccably preserved farmstead is a time capsule of a Pulitzer Prize-winning novelist's life.

An echo chamber with a waterfall wrapped around its base at the Embassy of Canada in Washington, D.C.

A piece of the Ludendorff Bridge, also known as Remagan Bridge, calls this military base home.

Long buried under the 20th-century landscape, this lift lock of the Alexandria Canal is the lone remnant of an ambitious early American transportation project.

The remains of a historic plantation nestled in between a parking lot and the rental car return at Reagan National Airport.

There’s a hidden military meme engraved on the World War II Memorial.

The "Seinfeld" diner.

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

This unassuming passageway played a key role in one of the most important events in U.S. history.

This nearly 200-year-old restaurant's history includes an exiled French prince, JFK, and a very hungry Daniel Webster.

The beloved, war-tested mascot of a Union regiment graces their battlefield monument.

The haunting remains of a failed housing development can still be found behind the big box stores that were to anchor them.

Railroad officials in the early 1900s sought to spare travelers the sight of Roman soldiers’ private parts.

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

One of the largest artillery pieces in the world sits in a Washington D.C. parking lot.

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

Its columns were all carved from the same white oak tree.

Sit where JFK proposed to Jackie or where Nixon dined on meatloaf at this storied pub.

Inside houses a vast collection of military aircraft and missiles spanning the ages.

The highway's southernmost spot is a beloved local attraction.

This museum sits on the site of a decommissioned military communications base.

This statue of one of baseball’s greatest pitchers looks like something out of a sci-fi horror movie.

It was once the base for a series of domestic terror attacks.