Knights of Pythias review (no. 1)
Marked on the verso in pencil as "Knights of Pythias Review" by the photographer planner Edward H. Bennett, this photograph is identified as a Grant Park celebration in 1917 by William Hudson Harper, Chicago: A History and Forecast, 1921, p. 166. The Chicago Tribune in 1917 indicates a "celebration" in Lincoln Park, July 28, 1917; but there could have been a parade on Michigan Avenue. In addition, the Knights of Pythias are among the groups on parade for Memorial Day, May 30, that first spring of World War I. The vantage point is atop the Railway Exchange Building, the location of Bennett's office, the former Plan of Chicago office, 1906-09. This is one of series of similar photographs.
Another possibility: Military Tournament on July 4, 1910 in Grant Park (Chicago). (from item 1897)