Two massive rock outcroppings on the Oregon coastline.

Rising from the sea like a stone monster.

A very big rock just plopped down in the New England woods.

Rippling sand dunes frozen in the Arizona rock.

The fossilized remains of ancient California redwoods.

A massive underwater sinkhole made famous by Jacques Cousteau.

Towering basalt columns, a creation of fire and ice.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

Native American burial mounds? Giant gopher dens? No one knows what created the Mima Mounds.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

"Only the devil could play golf here."

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

The largest cave shaft in the world is home to thousands of birds and popular with BASE jumpers.

Extraordinary sculpture garden created by an eccentric English poet.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

Treehouse motel and treehouse-building school.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

An island said to shake with the current.

A vertically floating hemlock controls the waves and weather at Crater Lake.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.