A large lava tube that can be walked through with no special equipment.

This hiking/biking/horse trail along an old railroad grade features trestles, tunnels, and a roadless stretch through the scenic Susan River canyon.

A colossal concrete penguin announces this Montana town as the coldest spot in America. But is it really?

An adorably sweet display of sculpted Precious Moments figurines.

A 35-foot-tall fork stuck in the ground outside an office building in Missouri.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

Bronze sculpture paying homage to Norma “Duffy” Lyon, famous for creating a life-size cow made of butter at the state fair.

The site where Joseph Smith, founder of the Latter Day Saint movement, was killed by a mob.

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

An idle pastime becomes a record holder in Boys Town, Nebraska.

A brick-paved former section of the historic coast-to-coast highway.

The World's Largest Bull.

A half-mile long and three stories high, this bridge over the Des Moines River Valley mimics a descent into a mine shaft.

This was the first homestead registered after President Abraham Lincoln signed the Homestead Act into law.

Over 30 brightly painted Dala horses roam through ‘Little Sweden.’

It's big, it's a ball, and it's made of twine—the world's largest of its kind.

Small plaque marks the spot, but the true center is located about half a mile away on a private pig farm.

The grandson of a Kiowa chief created what has become the iconic symbol of a city on the Plains.

A mysterious and terrifying public art goblin seemingly meant to inspire local legend.

Where the author wrote her beloved "Little House" books.

A town honors its legacy of traditional American Indian pipe carving with one gigantic pipe.

More than 7,000 gallons of water pour over these cascading red quartzite waterfalls every second.

The largest natural travertine bridge in the world is nestled in a small canyon in central Arizona.

The smallest post office in the United States is no bigger than a broom closet.