Geology

Massive crater in central Oregon.

Natural earth mounds formed in the far north.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

Virgil's many-mouthed gateway to the underworld.

This "floating island" plateau sits 7,671 feet above the forest floor.

A salty cave excavated by elephants and the location of a deadly disease vector.

One of the world's largest salt caves is filled with fragile salt sculptures, salt rivers, and huge salt megadomes.

A remote forest of stone pillars along the Lena river.

Strange sandstone canyon known as the "place broken by itself."

Cave on extinct volcano, once home to famous mathematician Pythagoras.

Legend holds eating just one of these black eggs can add seven years to one's life.

Natural catch-basin rocks covered in thousands of drawings spanning many millennia.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Towering basalt columns, a creation of fire and ice.

Amöneburg is a town perched on top of a basalt mountain in the middle of an ancient meteor crater.

A man-made slag heap that you can "ski" down, and is home to the world sandboarding championships.

A Swedenborgian glass church surrounded by redwoods sits perched atop a massive landslide area.

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