The ancestral chain Sagara – Asmanjas – Anshuman – Dilipa – Bhagiratha.
King Sagara had lost 60,000 sons who could only find salvation through the descent of Ganga.
Everyone in the ancestral chain tried hard – it was Bhagiratha who brought the Ganga to earth.
Ganga becomes Ganga in Devprayag, where the rivers Alaknanda and Bhagirathi converge.
For the story of Ganga visit
http://hindumythologyforgennext.blogspot.com/2012/01/story-of-ganga.html