Buddhists have schematized the possible life realms into six main categories. The "six realms of migration" are graphically represented everywhere throughout Tibet and elsewhere in the Buddhist world in the "wheel of life" often found on temple walls. This figure represents the experience of the dying person, who flies into the "mouth of Death" and lands on the wheel of egocentric life according to his or her evolutionary momentum.
-Excerpted from The Tibetan Book of the Dead as translated by Robert A.F. Thurman

Image used by permission: Tibet House