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

The hidden offices underneath Memorial Bridge have been locked up since 1976.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

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

The only National Monument ever to go missing for nearly 50 years then resurface in a dump.

Rumor has it the hot dog stand was targeted by two Russian nuclear missiles.

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

The rogue roots are gradually consuming some of the historic marble grave markers.

Born a slave on the Arlington estate, Parks dug the first graves at Arlington National Cemetery, and was buried there, too.

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.

The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

A gift from Scotland to the United States in memory of the 270 lives lost when Pan Am Flight 103 exploded over Lockerbie due to a terrorist bombing.

In what is rumored to be an intentional act of spite, this memorial almost completely obscures the nearby grave of a senior officer.

The naval commander’s proudest moment in battle is memorialized in this unique tomb at Arlington Cemetery.

Affectionately known as "Lord Bot," this historic statue has a cult social media following and rightly claims to be “the most metal inhabitant of the Wren Yard.”

America's first public mental health facility.

This museum explores the grim reality of life in the earliest British colonies in America.

Once the primary source of ice in this region during the mid-20th century.

Florida’s half-sized replica of the Vietnam Veterans Wall.

A local landmark with generations of spraypainted messages, and more being added each day.

Pensacola's UFO home has withstood many hurricanes—just as the experimental 1960s design intended.

Though nicknamed the “Russian Freighter,” this ship was actually sunk off the coast of Pensacola by the U.S. government in a top-secret operation.

This small memorial is almost as well concealed as Smalls himself was on the night he sailed to freedom.