Mythology was a collection of myths (a mythos, e.g., Inca mythology), considered an important feature of many cultures. A myth is a sacred narrative explaining how the world and humankind assumed their present form, although, in a very broad sense, the word can refer to any traditional story. Myths may arise as either truthful depictions or over-elaborated accounts of historical events, as allegory for or personification of natural phenomena, or as an explanation of ritual. They are used to convey religious or idealized experience, to establish behavioral models, and to teach.