Over 100 million people Hindu devotees are expected to attend the Maha Kumbh Mela.
Hindus bathe in the confluence of three rivers to wash away their sins.
Hindus believe when Gods and demons fought over a pitcher of nectar a few drops fell in four cities, including Allahabad where this Kumbh Mela is taking place.
Naked Hindu holy men wearing marigold garlands bathe in the river.
A member of an Indian brass band checks his instrument ahead of the procession.
Water police rescue one of the sadhus (holy men) stuck in the mid flow at Sangam, the confluence of the rivers Ganges, Yamuna, and mythical Saraswati.
To prepare for the event, authorities have set up 14 temporary hospitals and 243 doctors are on call, according to the BBC.
Authorities have also set up 40,000 toilets and deployed 30,000 policemen.
The Kumbh Mela is said to cost Rs. 11.5 billion or $210 million.
And it is expected to generate business worth Rs. 120 billion or $2.2 billion.
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