The Pan-American Exposition was a World's Fair held in Buffalo, New York, United States, from May 1 through November 2, 1901. The fair occupied 350 acres (0.55 sq mi) of land on the western edge of what is now Delaware Park, extending from Delaware Avenue to Elmwood Avenue and northward to Great Arrow Avenue. It is remembered today primarily for being the location of the assassination of United States President William McKinley at the Temple of Music on September 6, 1901.
https://en.wikipedia.org/wiki/Pan-American_Exposition