Some of the most interesting visual aspects of our environment often go unnoticed because of their familiarity. We are so much accustomed to them that we hardly pay attention to their intricacies, even less to our ability to rely on them in everyday behaviors. A convincing example is how water affects the appearance of surfaces, through both microscopic and macroscopic effects. Virtually everything changes: colors, shadows, gloss, geometry, etc., in ways that depend on the type of surface that is wet. Why is that so?