400 million people attended the world's largest gathering, India's Mahakumbh Mela, and Nat Geo photographer and Explorer George Steinmetz was there to capture this footage featured in our Pictures of the Year 2025. Every 12 years, an enormous tent metropolis is temporarily erected for pilgrims celebrating the Hindu festival of Kumbh Mela and seeking absolution at the Ganges and Yamuna rivers. This year's festival was particularly significant, occurring during an astrological conjunction that onl