Geology

Oregon's only closed-basin hypersaline lake, an important stopover for migrating waterfowl, is in danger of drying up completely.

A small mountain made entirely of banded iron stone overlooking downtown Ishpeming.

Stay in an old lookout cabin atop Oregon's spectacular Winter Ridge.

This spectacular fault escarpment, a popular hang-glider launch point, extends some 30 miles long and towers about 2,500 feet over the valley floors to the west.

The top of the holy mountain for the ancient Spartans looks like a pyramid—is it man-made or a natural phenomenon?

The world's largest mineral hot springs is home to a herd of bison, a free public bath house, beautiful mineral formations, and a terrifying swinging bridge.

An underground spring in a labyrinthine cave system, decorated with stalagmites and stalactites.

The original building of a mining school endowed by one of the barons of the Comstock Lode now houses a museum of earth science and mining history.

Crystal hunters can dig for their own stones at this DIY mine in Arkansas’ quartz belt.

One of Indiana's only natural sandstone arches is nestled between resort ruins and an old Boy Scouts camp.

This steaming, yellow-tinged landscape is filled with sulfur-encrusted volcanic vents.

Red ocher pictographs survive in this tufa rock shelter on the shore of an ancient lake.

One of the breathing caves of Australia's Nullarbor Plain.

These oddly shaped pink granite formations got their name after being mistaken for massive piles of hay.

This distinctive snowfield on the slopes of a Colorado fourteener has several legendary origin stories.