Tracks and Trenches
Tracks and Trenches Part of the "McMurdo" panorama taken at a spot in the Columbia HIlls where the rover Spirit passed a harsh Martian winter. As it drove backward to this spot, dragging its inoperable right front wheel, Spirit dug trenches that turned up sulfur-rich salty minerals, another hint at a watery past. NASA / JPL-Caltech / Cornell

"We're changing the world. Are you in?"
- CEO Bill Nye

Sign up for email updates