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 tribute to the pop culture icon overlooks this Washington D.C. intersection.

D.C. once had its own tiny rival to the New York Stock Exchange.

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

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

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

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

Before founding the American Red Cross, Clara Barton had a tremendous humanitarian impact by locating thousands of missing soldiers.

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

Art deco landmark on the outskirts of Washington, D.C.

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

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

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

The house where John Wilkes Booth conspired with his co-conspirators.

The national park was once a plantation estate.

The oldest continuously operating fish market in the United States.

Home to items never before seen by the public.

A model of a dinosaur that was named for Andrew Carnegie stands outside the museum that also bears his name.

The last street in Pittsburgh that's paved with wood.

The world's third-largest crystal sphere has sat in the Penn Museum since 1927 with the exception of one outlandish theft.

Despite being stolen multiple times, this civic electrician's street corner Snoopy won't be stopped.

A local prank turned town icon.

Ant sculptures march up the side of what used to be an iconic spot in punk rock lore.

The oldest farmer's market in America is so ancient it was approved by the King of England.