Yosemite Valley and Mariposa Big Tree Grove were combined and established as Yosemite National Park on this day in 1890. Several years before, President Lincoln signed over the grounds to the state of California as an inalienable public trust, marking the first time in American history that land was set aside for environmental preservation and the enjoyment of the public. Conservationists had appealed to the government that beautiful land such as Yosemite’s wouldn’t survive without protection. As a result, Yosemite became America’s first national park and today attracts more than four million visitors per year.