The Narrow Angle Camera of the Mercury Dual Imaging System (MDIS) on the MESSENGER spacecraft obtained high-resolution images of the floor of the Caloris basin on January 14, 2008. Near the center of the basin, an area unseen by Mariner 10, this remarkable feature, nicknamed "the spider" by the science team, was revealed. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
