This false-color image shows the area inside "Endurance Crater" that the Mars Exploration Rover Opportunity has been examining. The rover is currently investigating the distinct layers of rock that make up this region. Each layer is defined by subtle color and texture variations and represents a separate chapter in Mars' history. The deeper the layer, the farther back in time the rocks were formed. Scientists are "reading" this history book by systematically studying each layer with the rover's scientific instruments. So far, data from the rover indicates that the top layers are sulfate-rich, like the rocks observed in "Eagle Crater." This image was taken on sol 134 (June 9, 2004) by Opportunity's panoramic camera with the 750-, 530- and 430-nanometer filters.