If there was life on Mars, one of the big whens, not ifs, would be when the closest and biggest of their two moons, Phobos, would finally crash on the Martian soil.
With dimensions 26.8x22.4x18.9 Kilometers, and orbiting Mars from 9378 Kms, Phobos has an oversized impact crater that casts long shadows on its inner walls.
MEADE 14” LX200 telescope, ST2K CCD Camera. Exposure time: 15 seconds in high resolution. Image development in CCDops, Adobe Photoshop CS5 Extended