Umbriel

"'Umbriel is a world of craters. Some are mere meters wide, while others stretch to over 200 kilometers. A never-ending landscape of ice and rock, covered in craters. Even the most prominent surface feature, a large deposit of an unknown white substance, lines the inside of an enormous crater along the equator.""This makes Umbriel a perfect world for Hab Domes, as the craters make for the ideal foundation in which to build the first cities, but if your goal is terraforming you're in for a world of lakes. Be sure to keep careful control of the sea level, or you might flood your cities!'"