Mercury, geologic map. Map of the Beethoven quadrant (also known as H-7) on the planet Mercury based on photographs taken by the Mariner 10 spacecraft. Black lines outline the shapes of craters, basins, ridges, faults and other notable landmarks. Colours depict the reflectivity (albedo), morphology and texture of regions on the surface. Mercury is the innermost planet in the Solar System. Its surface features extensive craters, basins and plains. The major feature at bottom left (red, grey brown, green) is the Beethoven crater which measures 643 kilometres in diameter