They march like a sea of people, walking toward the spot where they take holy baths, drawn by the hope that the bathing would bring them salvation.But when they leave — believing their sins have been cleansed by the redemptive bath — they leave with one thing in common: their foreheads display a sacred stroke of color.

At least 30 people were killed and over 30 have been injured in a stampede at the Maha Kumbh Mela, one of the world's biggest gatherings that occurs every 12 years.