Yggdrasil is the great ash tree at the centre of the Norse cosmos

In Norse cosmology, the universe is held together by Yggdrasil, a colossal ash tree whose roots and branches link the nine worlds - among them Asgard, home of the gods; Midgard, the realm of humans; and Niflheim, a primordial land of ice and mist.

The tree is bound up with Odin. To win knowledge of the runes, he hangs himself from its branches in self-sacrifice - and the name itself may mean “Odin’s horse,” a grim reference to the gallows. Creatures live throughout the tree: an eagle in its crown, a dragon gnawing a root, a squirrel carrying insults between them.

In the time before time, when nothing existed, there was only the tree Yggdrasil and the void.

Yggdrasil is also tied to the world’s end and rebirth: it is said to survive Ragnarok, the final battle, and to be the source of new life afterward - making it a symbol of order, sacrifice and renewal at once.