An arsenic-filled pool in the Grand Canyon takes on the appearance of a giant, overflowing pumpkin.

In a 345-million-year-old cave that's 200 feet underground, dinner awaits.

Eons ago, a rushing lava river formed this pristine passage through solid rock.

See massive fossils that are over 200 million years old in northeastern Arizona.

An abandoned facility that has become a place of ritualistic satanic worship, or so rumor has it.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

Most-visited and most-photographed slot canyon in the American Southwest.

Dramatic river bend surrounds a natural red-rocked pedestal.

Rippling sand dunes frozen in the Arizona rock.

The unusual burial monument of Arizona's first governor.

The first permanent memorial to a unique secret weapon of World War II.

A geological mystery on Camelback Mountain.

Thousands of Mexican Free-Tailed Bats soar around an abandoned storm drain at sunset each summer.

This striking public art installation is suspended above a public park, designed to gently move in the breeze.

A self-built castle made by a mysterious man.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

This strange seaside tower got its name from a wealthy eccentric who would hide coins among its stones.

This whimsical garden filled with fairies and incredible creatures has been enchanting children—and adults—since the 1970s.

A unique sculpture park that specializes in the huge and bizarre.

This strange, big-tailed beast became a Pennsylvania town's unofficial mascot.

This granite rock face is named for the magnificent reflection that occurs when the sun hits it just right.

A grove of "candelabra redwoods" deep in California's Lost Coast.

An architect's childhood fantasy treehouse made real.