Some symbols of immortality are the ankh in Egyptian mythology and the cross and peacock in Christianity. Other symbols are the ouroboros in several myths, the phoenix in Christianity and legends around the world.
Symbols like the ankh and peacock are unique to specific cultural contexts while others like the ouroboros and the phoenix are universally recognizable. The ouroboros, for example, is an ancient symbol of a snake or dragon in a circle eating its own tail. It typically surrounds deities and symbolizes both creation and destruction by constantly re-creating itself. Besides mythology, it also appears in alchemical and Gnostic texts and in Jungian psychology. The Greek philosopher Plato stated that it represents the universe as an entity.
A symbol in many cultures, the phoenix is a long-living solar bird that periodically creates a fire to die and be reborn from the ashes. Texts state it can live from 500 to more than 1,400 years before rebirth. Its origin is in the literature and poetry of the ancient Greeks and the early Christians who adopted the theme. There are various cultural interpretations, but commonalities include the bird always having fiery feathers of yellow, orange, red and gold and always resurrecting from its own death.