The Marble Caves sit on the shores of a turquoise glacial lake in southern Chile. Light bounces off the water onto the walls, ...

These human-size crystals formed in especially strange ways. New clues into ancient climate shifts reveal the possible origin story of Spain's Pulpí Geode, one of the world's largest.

From the Decorah Ice Cave to Maquoketa Caves State Park there are more than 1,000 caves in Iowa. Here's a guide to seven of the most popular, all in one area of the state.

Clouds form when water vapor—an invisible gas in the atmosphere—sticks to tiny floating particles, such as dust, and turns into liquid water droplets or ice crystals.In a newly published study ...

Clouds form when water vapor — an invisible gas in the atmosphere — sticks to tiny floating particles, such as dust, and turns into liquid water droplets or ice crystals.In a newly published ...

Clouds form when water vapor – an invisible gas in the atmosphere – sticks to tiny floating particles, such as dust, and turns into liquid water droplets or ice crystals.In a newly published ...