the Ganges, the six longest and their five confluences are considered sacred. The six headstreams are the  Alaknanda ,  Dhauliganga ,  Nandakini ,  Pindar ,  Mandakini , and  Bhagirathi  rivers. The five confluences, known as the  Panch Prayag , are all along the Alaknanda. They are, in downstream order,  Vishnuprayag ,