1971: The Twenty-sixth Amendment to the U.S. Constitution was ratified giving the right to vote in all federal, state and local elections to persons 18 years and older. Before this time, the age was 21.

1864: President Abraham Lincoln signed the Yosemite Valley Grant Act, Senate Bill 203. The legislation gave California the Yosemite Valley and the nearby Mariposa Big Tree Grove "upon the express conditions that the premises shall be held for public use, resort, and recreation." The newly appointed Yosemite Board of Commissioners confronted the dual task of preserving the magnificent landscape while providing for public recreation. With remarkable foresight, board member and landscape architect Frederick Law Olmsted recognized that these goals could conflict. In his 1865 Draft of Preliminary Report upon the Yosemite and Big Tree Grove, Olmsted warns that "the slight harm which the few hundred visitors of this year might do, if no care were taken to prevent it, would not be slight, if it should be repeated by millions.