This enhanced-color image from the MESSENGER mission shows (from left to right) the craters Munch, Sander, and Poe. The hollows are the bright blue areas covering the floor of Sander and dotting the rims of Munch and Poe. The hollows are highly reflective and naturally appear bluish, but the spacecraft’s camera used color filters to exaggerate the spectrum in this image. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution for Science