Helheimr or Hel (Old Norse helheimr = 'realm of the dead') is one of The Nine Worlds in the Northern mythology. It is the realm of the goddess Hel and of the dead. It is not a place of punishment but simply a residence of the dead. The fence surrounding it is called Helgrind (also Nágrind and Valgrind).
People who have died on land of illness or of old age are admitted (the drowned belong to Rán and the fallen in battle to Óðinn). Once in Helheimr, the dead can never leave again. [1] [2]