Hetch Hetchy is a glacial valley located in Yosemite National Park in California. It is known for its stunning natural beauty, featuring granite cliffs, waterfalls, and diverse ecosystems. The valley is also home to the Hetch Hetchy Reservoir, which provides water to the San Francisco Bay Area. The reservoir was created in the early 20th century when the valley was dammed, leading to significant environmental controversy. Many conservationists, including John Muir, opposed the dam, arguing that it destroyed a unique natural landscape. Today, Hetch Hetchy remains a site of interest for both visitors and environmental discussions.