On September 6, 1901, President William McKinley held a public reception at the Pan-American Exposition in Buffalo, New York. In the receiving line, holding a gun concealed by a handkerchief, was Leon Czolgosz, a young man with anarchist leanings. When he reached McKinley, Czolgosz fired two shots, one of which would prove fatal. The backdrop of the assassination was among the largest of many world's fairs held in the late 19th and early...