Hel is one of the nine worlds of Norse mythology. It is where the mortal dead gather after life if their death was dishonourable. Its ruler is the goddess Hel. Hel is located under the roots of the tree Yggdrasil. It can be reached via the river Gjöll. A bridge spans this river which is guarded by the giantess Modgrudr. Garm, a dog, guards the entrance to the castle of Hel. He only lets the dead souls enter however they cannot leave. A rooster is the companion of Garm. Its purpose in the realm of the gods is to wake them for Ragnarök, this rooster will also wake the souls of the dead.