Contrary to what you might think, the cranium isn’t made out of just one bone. The human skull consists of twenty-two bones – eight cranial bones and fourteen facial skeleton bones. Except for the jaw, all of these bones are fused together by sutures (immovable joints), hence they tend to act as one.
David Tennant fulfilled a pianist’s dying wish by using his skull in a performance of Hamlet.
Incans in Peru would purposely deform infant heads to stretch their skulls out permanently; the nobility would have significantly longer skulls than everyone else.