Though his role as the inventor of baseball may be up for debate, fans still festoon Doubleday's grave with baseballs.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

An oft-overlooked, magically musical monolith that stands majestically between Arlington Cemetery and the Iwo Jima Memorial.

Right next to departures—how convenient!

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

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

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

The national park was once a plantation estate.

Largest Roman Catholic church in North America.

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

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

After James Madison's death, his wife and former First Lady Dolley Madison lived in this yellow building near the White House.

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

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

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

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

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

This taxidermy horse was a Civil War hero.

The only Leonardo Da Vinci painting in the Western Hemisphere.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

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