Intensely colorful calcite pools in Southern China.

Clusters of huge boulders in the Australian Outback.

Highly spherical boulders on the shores of New Zealand.

Massive rock sculptures formed during the time of the dinosaurs still stand undisturbed.

Largest site of dinosaur footprints ever found includes more than 5,000 tracks.

Remote, volcanic island that Darwin, Hooker, and the Royal Navy shaped into a thriving, artificial ecosystem.

Rocky Atlantic beach home to a stunning stone arch.

Singing sand that stands as the final remains of an ancient lake.

Friction between grains of sand cause a curious "singing" sound.

Museum about life, death, and cannibalism in the Stone Age.

Mile-long cave system near Great Smoky Mountains.

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

Modern-day cave dwellers carve elaborate homes out of volcanic debris.

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

The largest source of fossilized insects anywhere.

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

Fire meets ice at the southernmost volcano on Earth.

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

The rocks of a certain area of Butte, Montana give off a musical ring when hit.

The meteor that sealed the fate of the dinosaurs landed at this site, one of the largest impact craters in the world.

This giant boulder is pinched over a 1000-meter abyss by two mountains.

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

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

A massive underwater sinkhole made famous by Jacques Cousteau.