This old-fashioned carhop restaurant gave the world the waffle cone.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

This experiment in the lifespan of seeds will take a century before it is complete.

This mechanical wonder towers above a river in Michigan's capital city.

A horse-drawn 1858 steam pumper fire engine encased in glass on the front lawn of a Michigan insurance company.

Perched atop a brick smokestack, this enormous lug nut symbolizes the local minor league baseball team.

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.

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

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

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

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

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

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

The "lovely red Vega" of the legendary record-settling pilot.

It was once the base for a series of domestic terror attacks.

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.

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

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

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

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

A tiny piece of the Moon is embedded in this stained glass masterpiece.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

A precariously balanced rock perches on the edge of a cliff created tens of thousands of years ago by glacial erosion.