Gangasagar is located in the Ganges delta, lying on the continental shelf of Bay of Bengal. Every year on the day of Makar Sankranti (14 January), about 500,000 Hindu pilgrims gather to take a holy dip at the confluence of river Ganges and Bay of Bengal and offer prayers (puja) in the Kapil Muni Temple.
It is believed that a holy man, Kardam Muni, made a pact with Vishnu that he would undergo the rigours of marital life, on the condition that Vishnu would incarnate as his son. In due time Kapil Muni was born as an incarnation of Vishnu and became a great saint. Kapil Muni’s ashram was located on the island. One day King Sagar’s sacrificial horse disappeared; it had been stolen by Indra.
The king sent his 60,000 sons to find it, and they found it next to Kapil Muni’s ashram, where Indra had hidden it. Mistaking Kapil Muni for the thief, the sons accused Kapil Muni, who in his wrath at the false accusation burned the sons to ash and sent their souls to Hell. Later having compassion for the King Sagar’s sons, Kapil Muni acceded to the prayers of King Sagar’s descendants, agreeing to the restoration of the sons, if Parvati in the form of the river goddess Ganga would descend to Earth to perform the burial ritual of mixing the ashes with holy water (niravapanjali).
Through deep meditation, King Bhagiratha induced Shiva to order Ganga down from heaven and the 60,000 sons were freed (moksha) and ascended to Heaven, but the river Ganges stayed on the Earth. The date of the descent of Ganga according to modern calendar was 14 January, which coincides with Makar Sankranti (a Hindu festival).
The Gangasagar fair and pilgrimage is held annually on Sagar Island’s southern tip, where the Ganges enters the Bay of Bengal. This confluence is also called Gangasagar. Near the confluence is the Kapil Muni Temple. The Gangasagar pilgrimage and fair is the second largest congregation of mankind after the triennial ritual bathing of Kumbha Mela.