20 km from Karna Prayag, Nand Prayag at 914 m forms the confluence of the Alaknanda & Mandakini (flowing from a glacier near Nanda Devi Peak) rivers. It is said that confluence is named for the pious Raja Nanda. According to one legend, the king had been promised the boon of Vishnu as a son. Unfortunately, the same boon had been granted to Devki, the sister of the tyrant king, Kansa who imprisoned her. Ultimately, the gods found an ingenuons solution: Vishnu would be born as Krishna to Devki but would be brought up by Raja Nanda's wife, Yashodha.