Ancient mythology and planetary alignments draw Hindu holy men and pilgrims to the Maha Kumbh festival, but it's cutting edge technology that is entertaining the faithful this year, as well as keeping them safe. Organisers estimate around 400 million people will make their way to northern India this year to bathe in Prayagraj's sacred rivers. (AP Video shot by: Piyush Nagpal, Rishi Lekhi and Shonal Ganguly)