One year ago on January 3, the Mars Exploration Rover 1 -- more popularly known as "Spirit" -- landed successfully on Mars. MER 2 -- or "Opportunity" -- has its landing anniversary on January 24. MER 1 & 2 are easily the most successful Mars missions ever, and quite possibly the most successful (in terms of new discoveries made, new technologies tried, and ongoing results) space missions ever. The rovers were only supposed to last three months, and while most of the engineers expected to go well beyond that, few anticipated that both would be this healthy a year out. They've lasted through the worst of the Martian northern hemisphere winter, and spring should give them more sunlight (=more power) to work with. Of course, the year's just half-over on Mars; the Martian year lasts 687 days (Earth days, that is --Mars spins 669 times in the same period). NASA's MER mission site has the scientists' top 10 images from the two rovers, 25 favorite raw images, videos, maps, daily updates and much more information.