Kumbh Mela

The Kumbh Mela is a major Hindu pilgrimage and festival held every 12 years, typically at four riverside sites: Prayagraj, Haridwar, Nashik, and Ujjain. The festival is marked by a ritual dip in the waters, and is also a celebration of community commerce, education, and entertainment. It is traditionally credited to Adi Shankara, but there is no historical evidence of the festival prior to the 19th century. The modern Kumbh Mela is believed to have been rebranded and remobilized in the colonial era. The festival is observed for weeks, with millions of pilgrims participating, and is considered one of the largest public gatherings in the world.learn more on wikipedia