Yes. Keep in mind though that the - perhaps historically, perhaps still - most widely used kind of UML diagram - the class diagram - is just one component of UML.

Other than for explaining particular design patterns I don't find class diagrams all that useful, certainly not for giving you a complete picture of a system that consists of more than a handful of classes.

Sequence diagrams, state diagrams, use case diagrams, basically anything that involves or describes activities: I think those are tremendously useful.