Kumba mela

The Maha Kumbh Mela is a massive Hindu pilgrimage that takes place every 12 years at four sacred sites in India: Prayagraj, Haridwar, Ujjain, and Nashik. It's considered the largest peaceful gathering of people in the world, with millions of devotees participating in rituals and immersing themselves in holy rivers.
The most recent Maha Kumbh Mela was held in Prayagraj from January 13th to February 26th, 2025.
The next Maha Kumbh Mela is scheduled for 2037 in Haridwar.