An earthwork sculpture built by Robert Smithson in the Great Salt Lake only reemerges during drought.

Jurassic Park—A Still Life.

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

These falls, sometimes called the "Niagara of the West," still put on a good show at the right time of year.

An exercise in patience and imagination, where Mother Earth turned common stuff into precious hidden treasures.

This playground sculpture of an icon from the past is dedicated to the children of the future.

This inanimate goat created by the "welding nun" has been helping to clean up the city of Spokane for more than 40 years.

The decorations were inspired by an unlikely missing treasure.

The king of U.S. high points towers over every other peak on the continent.

Four-story concrete hotel never opened to customers.

A copy of the famous bus used during the filming of 'Into the Wild' is on display at an Alaska brewery.

This mile marker stands at the unofficial end of a highway built to defend the United States from a Japanese invasion during World War II.

The sculpture's largest spire points directly toward the North Star.

North America's first frozen mummified remains of an ice age steppe bison, the 36,000 year-old mummy named "Blue Babe."

A hulking remnant of Alaska's industrial gold mining boom in the 1920s.

This frozen tunnel in central Alaska is both an engineering feat and a valuable climate classroom.

A trading post in the North Pole where children send letters.

The first North American landing spot for James Cook on his third voyage of discovery in the Pacific.

This secluded date farm can be reached only by following a bumpy, single-lane desert road.

Although it also features red, orange, and variegated cliffs of Navajo Sandstone, this state park is often overshadowed by its more famous neighbor.

Forget Hollywood, one of the biggest stars in the world can be found in Roanoke, Virginia.

The site of the one and only battle of Lord Dunmore's War.

These rows of World War II-era bunkers were the scene of some of the infamous Mothman sightings.

A retired tobacco farmer's pet project turned into a sturdy miniature city.