Title:[0749] Callisto from 2,318,000 km Caption:A Voyager 2 image of Callisto taken on 7 July 1979 from a distance of 2.3 million km. The numerous bright spots are impact craters. Copyright: Credit:National Optical Astronomy Observatories

Title:[0447] The Valhalla basin on Callisto Caption:The Valhalla basin, a multiple-ringed impact structure on Callisto, is about 600 km across. The image was taken by Voyager 2 from a distance of 350,000 km. Copyright: Credit:A NASA/JPL PHOTO

Title:[0750] Photomosaic of Callisto Caption:Photomosaic of Callisto composed of 9 Voyager 2 frames taken from 390,000 km (245,000 miles) on 7 July 1979. Its surface is completely covered in impact craters; it may be the most cratered object in the solar system. Copyright: Credit:National Optical Astronomy Observatories

Title:[4009] View of Callisto from Voyager and Galileo Caption:This mosaic was prepared from images obtained by three spacecraft: Voyager 1 (left side), Galileo (middle), and Voyager 2 data (right side). The Voyager data were taken in 1979 but left a 'gap' centered at longitude 290 degrees in the trailing hemisphere of Callisto. The Galileo photographed this area on its second orbit around Jupiter on 9 September, 1996. The resolution of the Galileo data is 4.3 kilometers/pixel (2.7 miles), meaning that the smallest visible feature is about 12 kilometers (7 miles) across. Copyright: Credit:NASA-JPL

Title:[4008] Large impact on Callisto`s southern hemisphere Caption:This mosaic of images showing a large 200 kilometer (120 mile) diameter impact crater on Callisto's southern hemisphere was obtained by Galileo spacecraft during its eighth orbit of Jupiter. This crater is characterized by a bright circular area surrounded by a darker material excavated and ejected by the impact. Copyright: Credit:NASA-JPL

Title:[4010] Callisto Crater Chain at High Resolution Shown in Context Caption:A portion of a chain of impact craters on Callisto is seen in this image taken by the Galileo spacecraft on November 4, 1996. This crater chain on Callisto is believed to result from the impact of a split object, similar to the fragments of Comet Shoemaker- Levy 9 which smashed into Jupiter's atmosphere in July of 1994. The smallest visible crater is about 140 yards (130 meters) across. Copyright: Credit:NASA-JPL

Title:[4054] Callisto Scarp Mosaic Caption:This mosaic shows an area within the Valhalla region on Callisto. The smallest details that can be discerned in this picture are knobs and small impact craters about 155 meters (170 yards) across. The mosaic covers an area approximately 38 kilometers (24 miles) across. A prominent fault scarp crosses the mosaic. This scarp is one of many structural features that form the Valhalla multi-ring structure, which has a diameter of 4,000 kilometers (2,485 miles). Scientists believe Valhalla is the result of a large impact early in the history of Callisto. Copyright: Credit:NASA-JPL