Pilgrims take a holy dip in the Ganges in Haridwar during the 2010 Kumbh Mela festival. The Police reported drowning fatalities as pilgrims unable to swim were swept away by the fast flowing river. 16 million pilgrims visited the 2010 festival making it the world's largest religious gathering. The water begins it's flow from around 18,000 glaciers that store a massive 12,000 square kilometres of freshwater. Together with snow-melt they contribute to the summer flow of Ganges and other major life giving rivers such as the Indus, Brahmaputra, Yangtze and Yellow Rivers.