John Muir (April 21, 1838 - December 24, 1914) was a Scottish-born American naturalist, author, and early advocate of preservation of wilderness in the United States. His letters, essays, and books telling of his adventures in nature, especially in the Sierra Nevada mountains of California, have been read by millions. His activism helped to save the Yosemite Valley, Sequoia National Park and other wilderness areas. The Sierra Club, which he founded, is now one of the most important conservation organizations in the United States. In his later life, Muir devoted most of his time to the preservation of the Western forests. He petitioned the U.S. Congress for the National Park bill that was passed in 1890, establishing both Yosemite and Sequoia National Parks. Because of the spiritual quality and enthusiasm toward nature expressed in his writings, he was able to inspire readers, including presidents and congressmen, to take action to help preserve large nature areas. He is today referred to as the "Father of the National Parks". He died of pneumonia in 1914 at age 76. California celebrates John Muir Day on April 21 each year.