This rustic old building is said to be the most photographed barn in America.

An architect's childhood fantasy treehouse made real.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A beautiful geyser under environmental threat.

The first declared National Monument in the United States.

A striking sculpture built to honor the women of the Lakota and Dakota Nations.

Thanks to a loophole in property ownership, this alleyway has become a cacophonous street gallery.

This prehistoric sinkhole lured exclusively male mammoths to their death, much to the delight of science.

Hidden behind Lincoln's head is a 70-foot-long chamber containing enamel plates documenting American history, sealed in a teakwood box in a titanium vault.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

People of the Plum Bayou culture built these enormous mounds over 1,000 years ago.

Home to a seasonal waterfall and swimming hole in the Ouachita Mountains.

Life-size figures portray depot attendants, train crew, and passengers frozen in time at the oldest railroad station in Arkansas.

This historic hotel on Bathhouse Row in Hot Springs National Park has a storied history of gangsters and baseball greats.

An extravagant western hotel where every floor is the "ground floor."

This monumental Jesus is often referred to as "Our Milk Carton With Arms."

This haunted hotel built on natural springs once served as a hospital for a quack doctor promising a cure for cancer.

The farm toy capital of the world hosts a museum filled with toy tractors dating back to the late 1800s.

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

For just a few bucks, this Iowa funicular will let you feel like an 1800s fat cat.

A four story, football field-sized, nine-grotto creation made of shells, minerals, and rare stones.

Beating out all other concrete competitors, this massive garden feature's pointy hat has earned it a world record.