It is surrounded by the river Gjoll that flows from the spring Hvergelmir.  
It is surrounded by the river Gjoll that flows from the spring Hvergelmir.  In the form of an eagle, the giant Hraesvelg sits at the edge of this world and makes the incessant, cold wind blow by flapping his wings.  Its entrance is guarded by Modgud and another beast, and no one who enters may leave.  Home to those who die of old age and disease, it serves as the final resting place for anyone who does not die bravely on the battlefield.  Guarded by the hound Garm, FTP, identify this portion of Niflheim ruled over by a child of Loki and Angrboda.
It is surrounded by the river Gjoll that flows from the spring Hvergelmir.  
Helheim