The Kumbh Mela is generally held every three years in rotation at Allahabad, Haridwar, Ujjain and Nasik. Kumbh Mela is organized in the month of Magh according to the traditional calendar, which when converted to Gregorian turns to be Feb-March. The most important among these is the one celebrated at Allahabad. Due to the rotation system, the Kumbha Mela comes to Allahabad every 12 Years. The Kumbh Mela that runs for over a month is not only the largest fair in the world but also the largest conglomeration in the human world.
The Kumbh Mela that is also at times called Maha-Kumbh is held every 12
years on the confluence of river Ganges, Yamuna and Mythical Saraswati
are attended by devotes from all over the world. In fact, the last
addition of this fair saw 15 million people taking dip at the confluence
in a single day. This is still held in the record books. The total
number of people who took dip in the confluence on the 4 days reserved
for general devotees, stands around staggering 40 million!
There is a very interesting legend behind the Kumbh Mela. According to
the Hindu mythology it started with the very creation. It is said that
once Hindu deities asked for the help of Demons to churn the ocean. This
was done to centrifuge the 'Amrit' or 'Nectar' that would have in turn
made them immortal. Nevertheless when it came out, deities stole it and
didn't share it with the demons. It was hidden at four places in the
course of time and a drop of Nectar fell at all those places. These
places now hold Kumbh Mela. The main Kumbh is the day of Mauni Amavasya.
Other important bathing days are Makar Sankranti, Paush Purnima, Vasant
Panchmi, Maghi Purnima and Maha Shivaratri. The Ardh Kumbh Mela at
Allahabad is celebrated every 6th year in the month of Magh.