Inscribed on the UNESCO's Representative List of Intangible Cultural Heritage of Humanity, the Kumbh Mela is a mass Hindu pilgrimage of faith in which Hindus gather to bathe in a sacred or holy river. The festival is one of the largest peaceful gatherings in the world, and considered as the "world's largest congregation of religious pilgrims".
The Kumbh Mela is held at four destinations by rotation - Haridwar, Allahabad, Nashik and Ujjain. The main festival site is located on the banks of a river: the Ganges at Haridwar; the confluence of the Ganges, Yamuna and the invisible Sarasvati at Allahabad; the Godavari at Nashik; and the Shipra at Ujjain. Bathing in these rivers is thought to cleanse a person of all sins. At any given place, the Kumbh Mela is held once in 12 years. At Haridwar and Allahabad, an Ardha ("Half") Kumbh Mela is held every sixth year.  
According to medieval Hindu mythology, Lord Vishnu dropped drops of Amrita (the drink of immortality) at four places, while transporting it in a kumbha (pot). These four places - Haridwar, Allahabad, Nashik and Ujjain are identified as the present-day sites of the Kumbh Mela.