In March 1868 a 29-year-old John Muir stopped a passerby in San Francisco to ask for directions out of town. “Where do you wish to go?” the startled man inquired. “Anywhere that is wild,” said Muir. His journey took him to the Yosemite Valley in California’s Sierra Nevada, which became the spiritual home of Muir’s conservation movement and, under his guidance, the country’s third national park. “John the Baptist,” he wrote, “was not more eager to get all his fellow sinners into the Jordan than I to baptize all of mine in the beauty of God’s mountains.” Today around four million people a year follow their own thirst for the wild to Yosemite. Learn how the photographer composed these images.