Held only once every twelve years, the cleansing ritual of the Maha Kumbh Mela sees up to a hundred million Hindu devotees symbolically bathe away their sins in the holy Ganges River. It is thought to be the largest gathering of humanity on earth. For 55 days devotees wade into the river to bathe, and join other religious observations on the banks of the Triveni Sangam, the confluence of the Ganges, Yamuna and the mythical Saraswati rivers. Various sadhu and sadhvi (holy men and women) abound. The Maha Kumbh Mela began this year on January 14, with preparations starting weeks earlier. -- Lane Turner