n Norse mythology, the World Tree called Yggdrasill runs like a pole through this world and the realms above and below it. Yggdrasill is a great ash tree that connects all living things and all phases of existence.
Ulfberht Sword- viking sword made with forged steel. High carbon blade made this a very strong and durable weapon. See UTube or Netflix for 1 hour doc on how a modern day blacksmith recreated the sword using ancient techniques- way cool.