Svartalfaheim, in Norse mythology, the underground realm of the dwarfs, trolls, and gnomes. According to Norse mythology, the gods created the world after they had defeated the giants in an ancient struggle for supremacy. The three sons of the god Buri--Odin, Vili, and Ve--joined their father in the battle against the giants, and they were able at last to slay their greatest foe, Ymir, the father of the giants. The three brothers then took Ymir's body and placed it in the middle of Ginnungagap, the great abyss. From his flesh they created the earth, from his bones the mountains, from his teeth and broken knuckles the boulders and rocks, from his blood the seas and lakes and rivers, and from his hair the trees and the grass. They mounted his skull high above the earth to serve as the sky, and to support the sky, they placed dwarfs at the skull's four corners and named them East, West, South, and North. Then the gods scattered Ymir's brains throughout the space as clouds. As the gods were creating the world, maggot-like creatures were breeding in Ymir's remaining flesh. When the gods noticed their existence, they endowed these creatures with intelligence and human appearance. Some of these creatures became fair and good. The gods named them fairies and elves, and they were sent to Alfheim, a realm that existed between heaven and earth. Others became dark and treacherous beings called dwarfs, trolls, and gnomes, and the gods banished them to Svartalfaheim, the underground realm of the dwarfs. They dwelt under the ground and in the mountains, and could not come forth during the day for fear of turning into stone. The dwarfs of Svartalfaheim were most useful to the gods. The dwarfs were small and ugly, but clever miners and metalsmiths, and no one could equal them at this. All fine weapons and precious stones were made by the dwarfs. However, true to their nature, the dwarfs hated both gods and mortals, and when they were forced to work for them, they usually tried to make the objects in such a way that they would harm the owner.