A Christmas present from NASA: a new image of Saturn from the late great Cassini probe.
This shows Enceladus, the sixth-largest moon. The surface is highly reflective clean ice, and there's at least one ocean of liquid water underneath, some of it spewing into space through cryovolcanoes. You can just see one of these plumes as a smudge beneath the south pole of the moon.
NASA/JPL-Caltech/Space Science Institute