In Norse mythology, Hvergelmir is one of the three wells or springs at the roots of Yggdrasil. Hvergelmir means "roaring cauldron". It is in Niflheim.
The evil dragon Nidhogg, who ceaselessly gnaws at the root of the world-tree Yggdrasil, guards this spring. Eleven poisonous rivers, the Elivagar, flow from it, turning to glaciers that run into Ginnungagap.
The other two wells are Mímisbrunnr, Mímir's well, in Jotunheim; and Urdarbrunnr, Urda's well, guarded by the Norns, in Asgard.