In Norse mythology, there is an incredibly gigantic tree, with its branches extending across the sky, and legend has it that its branches form the entire world.
In Norse mythology, the great god Odin once hung himself upside down beneath this tree, offering one of his eyes and himself as a sacrifice, wounded by a spear as the price to gain wisdom, acquiring knowledge of the runes.
In Norse mythology, there is a poem in a self-narrative tone that records Odin's experience at the time: "Nine nights I hung on the tree swaying in the fierce wind, wounded by a spear; I was offered to Odin as a sacrifice, sacrificed myself to myself, on the mighty tree no one knows! No bread to satiate hunger, no drop of water to quench thirst. I looked downward, picked up the rune characters, shouting while picking, falling from the tree."
