Kumbha Mela is a major pilgrimage and festival for Hindus. It takes place in a cycle of approximately 12 years at four river-bank pilgrimage sites: the Allahabad (Ganges-Yamuna Sarasvati rivers confluence), Haridwar (Ganges), Nashik (Godavari), and Ujjain (Shipra).ImageSource
It is to be considered that the festival is traditionally credited to the 8th-century Hindu philosopher Adi Shankara, as a part of his efforts to start major Hindu gatherings for philosophical discussions and debates along with Hindu monasteries across the Indian subcontinent.
Millions of people gather at the course to bathe in the holy river. The massive gathering can also be seen from space and, on 10th February 2013, more than 30 million people gathered in a single day! It has also been awarded the status as a cultural heritage by UNESCO.
As per one of the Hindu beliefs, The Kumbh Mela derives its origin from a legend; describing a war between gods and demons over possession of the elixir of life which took place at the time of ‘Ocean-Churning’. To prevent the demons from seizing the Amrita (the elixir of eternal life), gods placed it in a Kumbha (a pot). The Kumbh Mela derives its name from this pot of nectar. The Kumbh Mela is celebrated four times over a course of 12 years; because the battle between gods and demons ran for twelve days, and twelve days for the gods are equivalent to 12 years for humans.