The first green space constructed on an elevated viaduct.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

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

The iconic D.C. restaurant where the Cuban Missile Crisis was negotiated, now a Walgreens.

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

Cold War intelligence agents monitored communist embassies from an attic in a former pigeon coop.

People escaping slavery may have hidden inside a corpse vault.

This bridge over D.C.'s Rock Creek Park is sometimes called the "Buffalo Bridge" because of its four buffalo sculptures, which were cast from a single piece of bronze.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

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

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.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

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

The sculptor was instructed to add “stallion attributes” to the general's bronze mare.

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

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

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

This restaurant has been a haven for D.C.'s LGBTQ community since the 1950s.

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

A diminutive memorial marks the site of a successful assassination by a right-wing death squad in America's capital.

A brass and marble scale model of the solar system embedded in the concrete.

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

Faceless white figures loom over the city from the rooftop.