Photographer Caleb Cain Marcus began his 1,500-mile pilgrimage along the the Ganges River amid the snow-capped peaks of Gangotri, India, a Hindu pilgrim town where the massive river originates as an aquamarine stream “so narrow that you could almost hop across.”

He’s not particularly religious, but for Marcus, following the path of the spiritually significant Ganges, which Hindus believe is synonymous with the goddess Gaṅgā herself, was an exercise in perception—in noticing the character and the energy of the atmosphere.

“We are often so busy with our lives that we don’t pay that much attention to spaces,” he says. “I feel that the air can have a presence. If you go into a church, or a mosque, or a synagogue,