The Mars robotic rover, Spirit, is slowly approaching the summit of a hill it's been climbing for almost a year. Spirit is one of two robotic rovers on Mars since January, 2004. It's driven three miles since it touched down on the three-billion-year-old volcanic plains of Gusev Crater. When Spirit reaches the top of the 80-meter Husband Hill, NASA scientists hope it will photograph a fabulous view. So far Spirit and Opportunity, the other rover, have investigated rock, rock, and more rock for clues about the red planet's past. Specifically, the rovers are searching for signs of layered rock that can form through the action of water. And both Spirit and Opportunity have found this kind of evidence for the past presence of water at their landing sites.