Bhagiratha
Bhagiratha was the king of Kosala (a kingdom in ancient India). He was a descendent of the great king Sagara of Suryavansha. He lost his father when he was just a child. So his mother brought him up. Bhagiratha was very intelligent, virtuous and kind hearted.
He brought the divine Ganga to the earth so that his ancestors (who had been burnt to ashes by sage Kapila could attain salvation.
To do this he left his kingdom and went to himalayas for a long Tapasya (Meditation to please Gods) for many years. Finally the Gods were pleased and thus came Ganga to the earth. See Ganga.
For this Ganga is also known as Bhagirathi (daughter of Bhagiratha).