Rubbing Stone, Washington

Photograph by Fritz Hoffmann, National Geographic

Looking as if it fell from the sky, a 40-ton erratic stands on the Colville Indian Reservation in Washington State. Such boulders are sometimes called rubbing stones because bison scratched up against them.

See more pictures from the March 2012 feature story "Rock … And Roll."

What Made This a Photo of the Day

The brilliantly starry sky makes a perfect backdrop for this ancient rock, reenforcing the sense of timelessness. It feels as if the boulder itself were as old as the cosmos above it. —Alexa Keefe, Photo of the Day editor