Gangotri, the origin of the River Ganges and seat of the goddess Ganga, is one of the four sites in the Chota Char Dham pilgrimage circuit. The original Gangotri Temple was built by the Gurkha general Amar Singh Thapa.
According to Hindu history, Goddess Ganga took the form of a river to absolve the sins of King Bhagiratha's predecessors, following his severe penance of several centuries.
Gangotri Temple Uttarkashi
According to this legend, King Sagara, after slaying the demons on earth decided to stage an Ashwamedha Yajna as a proclamation of his supremacy. The horse which was to be taken on an uninterrupted journey around the earth was to be accompanied by the King's 60,000 sons born to Queen Sumati and one son Asamanja born of the second queen Kesani. Indra, supreme ruler of the gods feared that he might be deprived of his celestial throne if the "Yajna" succeeded and then took away the horse and tied it to the ashram of Sage Kapil, who was then in deep meditation. The sons of the King Sagara searched for the horse and finally found it tied near the meditating sage. Sixty thousand angry sons of King Sagara stormed the ashram of sage Kapil. When he opened his eyes, the 60,000 sons had all perished, by the curse of sage Kapil. Bhagiratha, the grandson of King Sagar, is believed to have meditated to please the Goddess Ganga enough to cleanse the ashes of his ancestors, and liberate their souls, granting them salvation or Moksha.