Kumbh Mela is a Hindu pilgrimage that occurs four times every twelve years and rotates among four locations: Prayag (Allahabad), Haridwar, Ujjain and Nashik. Each twelve-year cycle includes one Maha Kumbh Mela (Great Kumbh Mela) at Prayag, which is attended by millions of people, making it the largest gathering anywhere in the world. It was actually started by King Harshvardhana of Ujjain. He used all his wealth to donate during this mela to poor,learned people of all religions.
The combined sanctity of the three holy rivers, coupled with the spiritual powers obtained from the pot of nectar of immortality has earned Prayag as tirtharaja ( the king of holy places). The confluence of India's three most sacred rivers at Allahabad , Besides the Ganges, there are also two other sacred rivers located at Allahabad, the Yamuna and the Saraswati . Ganges & yamuna has its earthly origin in the Himalayas. Whereas Saraswati, is a mystical river which has no physical form. Its is believed that the Saraswati exists only on the spiritual plane and is not visible to the human eye.