Students analyze primary sources to investigate the debate over damming the Hetch Hetchy Valley in Yosemite National Park, which marked a crossroads in the American conservation movement when San Francisco’s need for a reliable water supply, along with a new political dynamic at the federal level, created a division between those committed to preserving the wilderness and those more interested in efficient management of its use. After, students may conduct research to identify and develop a comparison with a contemporary controversy, such as opening protected areas to volcano monitoring or resource extraction in or delivery through these places.