The Hindu festival Maha Kumbh Mela kicked off in Prayagraj in Uttar Pradesh, India on Monday. The event takes place once every 12 years in the city, and draws hundreds of millions of people across six weeks.

The Maha Kumbh Mela has commenced in Uttar Pradesh’s Prayagraj on. The 45-day religious gathering is significant for Hindu pilgrims and devotees as the event marks the completion of 12 Kumbh Mela cycles,

While the Kumbh Mela festival is ordinarly held every three years, rotating between several holy cities on the banks of these rivers, the Maha Kumbh Mela occurs only once every 12 years. Maha means “great”, and the event attracts the most devotees because it is considered the most auspicious and holy in the cycle.

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.