What ? A mass Hindu pilgrimage, takes place every twelve years at one of the four places Allahabad, Haridwar, Ujjain and Nashik. During the battle between the gods and demons for the pot of amrita, the nectar of immortality, Lord Vishnu flew away with the Kumbha of elixir spilling drops of amrita at these four places
When ? In 2013 from 27th January to 25th February, in Allahabad (or Prayag), Uttar Pradesh, India
Major event ? The ritual bathing at the banks of the river Sangam (confluence of Ganga, Yamuna and mythical Saraswati) in Allahabad.