The Ganges, as indicated in the previous response, is seen as a life force of a river. The belief behind the river was that the river is the embodiment of the goddess Ganga, whose tremendous and powerful nature in the form of a river could not be handled by mortals. When a sage needed to be cleansed by the water offered by the goddess Ganga, the gods were confused. On one hand, they all agreed that the sage should benefit from the privilege of bathing in the river, yet they knew that the power of Ganga was far too powerful to be handled. Lord Shiva was moved by the sage's predicament and vowed to take responsibility for the river. Ganga believing herself to be strong and feeling a bit slighted by the great lord was committed to pouring down on the mortals in her most powerful of ways. Lord Shiva understood this and when she forcefully descended, Shiva smiled and wrapped one of the locks of his hair around the river. Being the supreme lord he was, Ganga had no choice but to relent, and since then the belief is that the Ganges descends from Lord Shiva's hair itself, part of the reason why it is seen with so much awe and reverence. When one bathes in it, they are partaking in the Lord, himself.
The Ganges River is a holy and sacred waterway to the Hindus in India, who believe bathing in it is a time honored ritual that cleanses the soul. Many Hindus believe that your life is somehow unfinished if you have not traveled to bathe in its waters at least once. You will find a vial of water from the Ganges River on the mantle of many Indian homes, and the river is a symbol of the religion and the gods they worship.
Dozens of religious temples are located along the river itself, and several religious holidays are associated with it. It is also believed the river is a sacred place to be cremated, and have your ashes scattered in the water or along its banks.
The holy river Ganges, originating from the Gangotri glacier in the Himalayas, is believed to be a source of life to the Hindus in India. The river is popularly called Ganga which is the name of a goddesss appearing in the epic Mahabharata.
In popular belief, bathing in the river leads to remission of sins and attainment of salvation. The Gangetic basin has been extremely fertile, and thus the river is associated with agricultural prosperity. So many Hindu pilgrimages such as Rishikesh, Hardwar, Varanasi & Allahabad are located in the shore of the river.
It is said that the river used to flow in the heavens, and was ordered to go down to earth. Forceful descent of the river might have washed the earth away. Lord Shiva broke the fall of Ganga by capturing her in his mighty locks.