Ansel Adams was the most important landscape photographer of the 20th century. He is also perhaps the most widely known and beloved photographer in the history of the United States; the popularity of his work has only increased since his death. Adams’s most important work was devoted to what was or appeared to be the country’s remaining fragments of untouched wilderness, especially in national parks and other protected areas of the American West. He was also a vigorous and outspoken leader of the conservation movement. -Britannica