Watch: Sea of humanity at world's largest religious gathering
The BBC's Samira Hussain reports from the northern Indian city of Prayagraj, where millions of people have already gathered on day one of the Mahakumbh Mela to take a holy dip at Sangam - the confluence of India's most sacred Ganges river with the Yamuna river and the mythical Saraswati.
Devout Hindus believe bathing in these waters will cleanse them of their sins and take them closer to spiritual liberation.
