A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

One of Philadelphia's largest murals resides hidden under this bridge.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

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

Current docking place of the SS United States, the fastest transatlantic ocean liner.

An Irish Memorial commemorating those who perished due to potato blight.

A unique set of caves that spits waves back out into the ocean.

The air force base preserves its scars from the Japanese attack on Pearl Harbor.

During the solar phenomenon "Lahaina Noon" this bendy, curvy sculpture forms a perfectly circular shadow on the ground.

The only royal palace on U.S. soil has been a territorial capitol, a military headquarters, and a prison for a queen.

Once the site of the Hawaiian monarchy, this building was originally designed as a palace.

An ode to one of the first concerts broadcast via satellite.

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

An out-of-place Air Force radar dome is all that denotes this park as a former missile launch site.

This former Cold War missile control site played an important role in the creation of GPS.

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

Need a hardcopy of the 50-title Code of Federal Regulations? This is the place.

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

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

A hidden passageway now marks the site of an assassination attempt on Ronald Reagan that some say broke a 140-year-old curse.

Also known as the Founding Church of Scientology.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

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

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.