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.

Vast crowds of Hindu pilgrims in India bathed in sacred waters as the Kumbh Mela festival opened on Monday, with organisers expecting 400 million people -- the world's largest gathering of humanity -- to assemble over six weeks.India is the world's most populous nation, with 1.4 billion people, and so is used to large crowds.

A six-week Maha Kumbh Mela or Great Pitcher Festival begins in India on Monday, a Hindu sacred event that will be the world's largest gathering of humanity as it showcases religion, spirituality, tourism and crowd management.

Millions of Hindu pilgrims are gathering in India to bathe in sacred waters for the six-week-long Kumbh Mela festival -- from the very old to babies, cave-dwelling monks to science teachers.The millennia-old Kumbh Mela,

The Maha Kumbh Mela, or the Great Pitcher Festival, will bring more than 400 million people to Prayagraj city in northern India over a period of six weeks starting Monday, making it the largest gathering of humanity in the world.

Held every 12 years, 2025's Maha Kumbh mela has seen the construction of 400km of temporary roads, a 10,000-acre pop-up tent city, 150,000 toilets, three hospitals and more.