Dyed by iron oxide over centuries, these sandstone rocks rise thousands of feet into the sky.

Ha Long Bay's "Cave of Surprises" houses a popular phallic rock formation.

Devilish landscape, once cinema home to giant alien bugs, now derelict roadside attraction.

Collection of fossils, plants, and ancient animals encased in amber.

The largest source of fossilized insects anywhere.

Made by river sediment, it is the largest alluvial fan in the world.

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

A city continually buried under the ash of a volcano that has been erupting for more than 15 years.

Site of the greatest known waterfall that ever existed.

Ethiopia's "smoking mountain" is in one of the hottest regions on the planet and is home to two lava lakes.

Fire meets ice at the southernmost volcano on Earth.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

Rising from the sea like a stone monster.

A massive, heart-shaped, wind-carved crater in the middle of the Israeli desert.

Home to nearly a third of the world's mud volcanoes, Azerbaijan is home to a messy, bubbling, and sometimes explosive landscape.

The largest known meteorite on Earth was too big to move.

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

An enormous pink granite batholith, long attributed with spiritual powers by the Tonkawa Indians.

Rippling sand dunes frozen in the Arizona rock.

Virgil's many-mouthed gateway to the underworld.

An island said to shake with the current.

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

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

Over fifty whirling pools left by the glacial age.