According to the legend at the beginning of the creation when the gods and demons were residing on the earth, the gods were under a curse by Saint Dhurvasa, which made them weak. So the gods decided to meet the creator, and ask for his advice. Brahma the god of creation advised them to retrieve the Kumbha containing the nectar of immortality, by churning the milky ocean.  Since the task was too sturdy for them alone, the gods decided to make an agreement with the demons that half the nectar will be given to them. During the churning, lots of celestial beings came and at last appeared the nectar of immortality. After churning the ocean for 1000 years finally Dhanavantri a divine physician appeared with the Kumbha full of nectar of immortality. The gods, being fearful of the demons’ ill intention, forcibly seized the pot, with its safety entrusted to the four Gods - Brahaspati, Surya, Shani, and Chandra. Demons upon knowing that the gods didn’t keep their promise went after the gods for 12 days and 12 nights (equivalent to 12 human years) chasing them. During the chase a few drops of nectar fell at four different places on earth, they are Allahabad, Haridwar, Ujjain and Nasik. These four places are believed to be having some mystical powers. Since then, when the planets align in the same position as during the churning, pilgrims and devotees converge to commemorate this divine event and reap the benefits of the event at those places.