Hindu holy men walk during a religious procession as they head to take a dip in Sangam, the confluence of Ganges, Yamuna and mythical Saraswati rivers, for Shahi Snan or 'royal bath', on the occasion of Maha Kumbh Mela festival, in Prayagraj. Organisers are expecting some 400 million people to attend the Kumbh Mela festival in northern India -- a six-week-long celebration of prayer and bathing that began before dawn on Monday. IMAGES