The old fire tower is one of the last of its kind in the United States.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

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

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

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

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

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

The walls of the iconic dome are hollow and have a secret stairway.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

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

The Pentagon sits on a former island that was in Virginia at low tide and D.C. at high tide.

Forget Hollywood, one of the biggest stars in the world can be found in Roanoke, Virginia.

At 207 feet, one of the world's longest continuous escalators.

One street divides a single town that stands in two U.S. states.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.

Legend has it the commander of the defenders drew a fateful line in the dirt with his sword just before the final battle.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

The short-lived history of a new republic and British control in West Florida.

The LSU mascot lived on the college campus in one of the most impressive tiger habitats in the country.

This strange, small castle on the bayou has withstood the test of time and weather.