World's longest ultra-marathon not finished yet.

Skier relied on arm strength alone for feat.

New evidence reveals a Death Valley crater is far younger than thought, and could be ready to blow.

Eruption of underwater volcano, resulting landslide recorded by submerged mic.

Maps of Arctic and Antarctica help track polar animals, train researchers.

Less snow and ice cover means more of the Sun's energy is absorbed by Earth.

Weird life forms may lurk under miles of ice.

Scientists struggling to get invaluable data sent home early.

Signatures in ancient rocks show continent's erosion history.

Study narrows list of possible 'light elements' in Earth's outer core.

No tsunami is expected to be produced by the temblor.

Preliminary magnitude of 4.4.

Fossils and native wildlife abound.

Machu Picchu has become a popular tourist destination.

Check out these winter wonderlands - and one warm retreat.

Rubbing creates unusual erosion patterns on rocks.

Evidence of past major temblors found around faults.

Camera will monitor climate change on the mountain.

The natural bridge is the 12th largest on the planet.

Inner gorges were preserved through different glacial periods.

Animation of Earth's snow cover over past decade.

Flooding from Hurricane Irene, fungus could mean fewer pumpkins.

This Greenland glacier produced a colossal ice berg last year, and may be set to do it again, thi...

Could provide information on when Greenland, Antarctica began melting.

$380 billion in damage, mostly from Japan earthquake and tsunami.

Eye-popping numbers on Texas' hellish weather.

Islands could change view of breakup of the ancient supercontinent of Gondwana.

Huge waves are the likely culprit, but scientists seek to know what kind of large wave.

Crystals took millions of years to reach current size.

Dripstones in Alps cave shed light on mountain growth, ancient climate.