As Pangea broke up and the plates drifted apart 200 million years ago, magma seeped out of the fissures in the Earth’s crust. That magma became flows of lava, and that lava, rapidly cooling in the air ...

Flag Hill, made up of fossiliferous sandstone of the Briones Formation, overlooks the Sunol Regional Wilderness. Photos by Andrew Alden The Sunol Regional Wilderness, part of the East Bay Regional ...

On the banks of the Columbia River, tall columns of rock poke out from the cliffs. “So you see all of these black rocks that are on either side of us, on either side of the river? Those are basalts.

At the base of a lush green hillock, a channel of water gurgles as it flows out of a reservoir, an 8th century engineering marvel deep in the heart of Telangana. Young men jump into the channel to ...