The meanings of the designs on totem poles are as varied as the cultures which make them. Totem poles may recount familiar legends, clan lineages, or notable events. Some poles are erected to celebrate cultural beliefs, but others are intended mostly as artistic presentations. Certain types of totem poles are part of mortuary structures incorporating grave boxes with carved supporting poles, or recessed backs in which grave boxes were placed. Poles are also carved to illustrate stories, to commemorate historic persons, to represent shamanic powers, and to provide objects of public ridicule.