A memorial dedicated to a highly decorated Marine and Korean War veteran, who also happened to be a horse.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

The romance of early commercial flight still fills this Art Deco destination.

A striking memorial to the 21 lives lost in an explosion at the Washington Arsenal

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

Corn-inthian columns with a uniquely American take on neoclassical architecture.

Washington's iconic carousel has a nice piece of Civil Rights history.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

On the Fourth of July this area will transform into a Pompeii-like storm of falling embers and ash.

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

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

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

This historic boathouse was constructed using salvaged lumber from burned barns.

The site of the climactic scene from the classic horror film is now a historic landmark.

Try not to get slimed in Tribeca.

Seriously good slices of Sicilian pizza lurk at the back of the Bronx's oldest enclosed market.

This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

The "Seinfeld" diner.

This memorial honors thousands of enslaved Africans and their descendants who died in colonial New York.

Pulled from the rubble of one of the worst modern tragedies, a steel crossbeam became a symbol of hope for New Yorkers.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

The home of the first American-born saint is one of the only curved buildings in New York.

Twice a day one of these tragic bronze mariners drowns with the tide to remember all those the sea has taken.

Now abandoned, the first public health hospital in the U.S. saw more than one million immigrants from around the world.