A lava tube cooled to form this long tunnel that stays chilly even at the height of summer.

The only bridge in the United States where BASE jumping is legal without a permit year-round.

Where the famed daredevil attempted to launch himself across a canyon in a custom-built rocket.

Home to a timed geyser created by complete accident.

Water flowed out of the town's unusual tree stump fountain in the 1930s, and the well still runs today.

On a wall in Cleveland, Ohio find the story of a highly connected fictional community of organisms that created remarkable, lasting structures.

The first declared National Monument in the United States.

Landmark dedicated to the plight of the American Indian in the 21st century.