Comparative immortality.

In India we find the story of the substance Amrita. Amrita is a word that
literally means "immortality" and is often referred to in ancient Indian
texts as nectar. "Amrta" is etymologically related to the Greek ambrosia.
Its first occurrence is in the Rigveda, where it is considered one of
several synonyms for soma, the drink of the devas. The photo is of the
goddess Mohini, the female form of Vishnu, holding the pot of amrita which
she distributes amongst all the devas.

In Norse mythology there is the goddess Iduna who guards the golden apples
of imortality. "Iduna, the Goddess, tended the tree on which the shining
apples grew. None would grow on the tree unless she was there to tend it.
No one but Iduna might pluck the shining apples. Each morning she plucked
them and left them in her basket and every day the Gods and Goddesses came
to her garden that they might eat the shining apples and so stay for ever
young."

In Greek Mythology we have the Hesperides, the daughters of Night, who
guarded the golden apples beyond Ocean in the far west of the world. One of
the twelve labors of Hercules is to go to the Garden of the Hesperides and
pick the golden apples off the Tree of Life growing at its center.

In China there is the legend of Queen of the west. A goddess who guards the
peach tree that grows the peaches of immortality that grows on mount
kunlun. Mount kunlun considered to be a central world pillar or axis mundi.

Some common elements of these and other similar stories is that the
substance of immortality is guarded by a goddess, has an association to a
tree and is located at some central world pillar. There is also some
crossing over event or entering a beyond the mundane realm before this
mythical destination can be reached.