Over about the next six weeks, Hindu pilgrims will gather at the confluence of three sacred rivers where they will take part in elaborate rituals.

Vast crowds of Hindu pilgrims in India readied on Monday to bathe in sacred waters for the Kumbh Mela festival, with organisers expecting 400 million people -- the largest gathering of humanity.India is the world's most populous nation,

India's Maha Kumbh Mela, or Great Pitcher Festival, is set to be the world's largest gathering of humanity, with 400 million visitors expected at the six-week event that began this week in the northern city of Prayagraj.