Yggdrasil is an immense and central sacred tree in Norse cosmology. It is attested in the Poetic Edda and the Prose Edda, and is considered very holy. Yggdrasil is an enormous ash tree that connects the Nine Worlds, including the underworld, the earth, and the realm of the gods. It is associated with both life and death, as it acts as a gallows from which the god Odin hangs himself to gain mystical knowledge, and it is said to be the source of new life after Ragnarök, the catastrophic final war of the gods. The name Yggdrasil is generally accepted to mean "Odins horse" or "gallows," reflecting its significance in Norse mythology. The concept of Yggdrasil has had a profound influence on Norse culture and remains a prominent symbol of the interconnectedness of all things in the natural world.