The largest riverfront opening cave in the Ozarks.

An unusual waterfall in the Santa Rosa Range, within the Great Basin of Nevada.

The Harlem Renaissance poet and activist wrote, organized, and hosted travelers in this Lynchburg, Virginia oasis.

The seventh largest spring in the world.

A nearly century-old amusement park is quietly decaying in a riverside forest in South Carolina.

An aptly-named street near the birthplace of the modern LGBT rights movement.

A historic bridge no one is allowed to cross.

Exhibits from an island in Lake Michigan are preserved in this hand-built cabin museum.

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

A vibrant colony of rescued wolves and other canids.

One of the stops along the fateful journey of the Donner Party.

Three bronze deer sculptures relax along the Scioto Mile.

A small Chicago museum filled with thousands of preserved butterflies, beetles, and more.

The cliff and rock formations are made out of Sioux Quartzite.

Dedicated to the "World's Luckiest Fishing Village."

Home to some of Indiana's last bison herds.

This mountaintop refuge rehabilitates tigers, lions, bears, and more from illicit wildlife trade—and offers overnight lodging.

The largest spring in Northwest Arkansas is also home to a sprawling botanical gardens and a historically significant bluff.

This restaurant serves wood-fired fare served in a natural cave with a live spring.

The first blast furnace in the United States that used coal and coke fuel instead of charcoal to make pig iron.

At the most northwestern point of the contiguous United States lies a trail leading through an ancient forest to stunning cliff-side vistas and massive oceanside caves.

Around 50 million gallons of water flow from this spring every day.

This bronze statue commemorates the strange and beloved mascot of UC Irvine—the only university to be represented by a giant anteater.

Memorials are nearly all that remains of this Arkansas prison camp, where thousands of Japanese Americans were forcibly relocated during World War II.