The Kumbh Mela, believed to be the largest religious gathering on earth, is a mass Hindu pilgrimage of faith in which Hindus gather at a sacred river for a bath in the river. It is held every third year at one of the four places by rotation: Haridwar, Allahabad, Nasik and Ujjain. Thus the Kumbh Mela is held at each of these four places every twelfth year.
The current Kumbh Mela began on 14 January 2013 at Allahabad (Prayag).
There is no scientific method of ascertaining the number of pilgrims even approximately and the estimates of the number of pilgrims bathing on the most auspicious day may vary very widely from two to eight million depending upon the team(s) of persons making the estimate and the rough method of making the estimate.