Despite its name, this fast food museum is actually a replica of the ninth McDonald's store.

The world’s largest truck stop includes a barber shop, chiropractor, and a huge museum with antique trucks.

A hidden barn-sized rendition of Grant Wood's most famous, and most parodied, painting.

The Iowa state contender for largest pan in the world oddly only comes in second or so.

Remnants of a quarry company town still stand on the banks of the Wapsipinicon River.

A pop-culture attraction outside of Dyersville, Iowa, hits a home run.

What is the Thing?

The outcropping is graffitied with the name of the beloved musical Muppet television series.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Bar full of oddities, specimens, artifacts and homages to the great dime museums of the past.

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.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

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

A building shaped like the Army Corps of Engineers logo, because why not?

An overlooked memorial honoring the local Washington residents who died in World War I.

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

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

There's a crumbling old mansion inside the Smithsonian National Zoo.

The oldest continuously operating fish market in the United States.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

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

Decades before the scandal, this staircase on the river was a literal "water gate."

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