Svartalfheim is one of the Nine Realms and is home to the Dark Elves. The Asgardians and other inhabitants of the Nine Realms refer to it as the "Dark World," while the Dark Elves themselves call it "Harudheen." Located in a star system that is almost completely corroded with dark matter, both Svartalfheim and the Dark Elves inhabiting it have developed under a more diverse table of elements. The only source of visible light for the world is a black hole.
In 2987 BC, Svartalfheim was the location of a destructive battle waged between an Asgardian army led by Bor against the genocidal Dark Elf forces under the command of Malekith. The battle ended in the Asgardians' favor, and the Dark Elves were driven nearly extinct with the exception of Malekith and a few dozen of his soldiers. The surface of the planet then became a deserted wasteland covered in battle torn deserts and wrecked Dark Elf warships.
In 2013, Malekith and his soldiers reawakened when Jane Foster discovered the Aether, and the realm became a battleground again when Malekith fought with Thor and Loki over the Aether's possession. The battle ended with Malekith leaving the planet and Loki faking his death in a battle with Algrim.
During the Battle of Greenwich, Thor and Malekith fought on Svartalheim briefly after being transported there via Convergence. Malekith was later teleported there by Erik Selvig using a transportation device, followed shortly by Malekith's spaceship, which crushed him to death.