Larry McMurtry, along with historians such as R.L. Wilson, asserted that at the turn of the 20th century, Cody was the most recognizable celebrity on Earth. While Cody's show brought an appreciation for the Western and American Indian cultures, he saw the American West change dramatically during his life. Bison herds, which had once numbered in the millions, were threatened with extinction. Railroads crossed the plains, barbed wire, and other types of fences divided the land for farmers and ranchers, and the once-threatening Indian tribes were confined to reservations. Wyoming's coal, oil and natural gas were beginning to be exploited toward the end of his life.