The Pan American Exposition was a World's Fair held in Buffalo, New York from May 1 through November 2, 1901. It is most notable because United States President William McKinley was shot by an anarchist, Leon Czolgosz, on September 6, 1901. The newly developed X-ray machine was displayed at the fair, but no one thought to use it on McKinley to search for the bullet, which might have saved his life.