The Kumbh Mela festival, the largest religious gathering in the world, has begun in the northern Indian city of Prayagraj.

Days before India started its mammoth Kumbh Mela festival, a video showing preparations for a nighttime light show surfaced in social media posts that falsely linked it to the six-week Hindu event. The video was in fact originally published by a US-based drone show company and shows a Christmas celebration.

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.

India began on Monday its Maha Kumbh Mela, or Great Pitcher Festival, which is expected to draw more than 400 million visitors to the northern city of Prayagraj over six weeks, making for the largest gathering of humanity in the world.