Nidavellir (meaning "the dark fields"; pronounced "nih-DA-vel-EAR") is one of the Nine Worlds and is the home of the Dwarfs. Being all underground, there is no sunlight and is instead lit by a special glowing moss. One section of Nidavellir is Svartalfheim.
Nidavellir is described as chilly and dark and the buildings are equally gloomy, though the furnishings are one-of-a kind creations.
Magnus Chase and Blitzen are here sent by Freya to get her new earrings. They then run into Samirah al-Abbas and Hearthstone. After the crafting contest they are chased out of the world and escape by jumping into a river.