The sport has the official site www.hardrock100.com . The venue for Chicago Marathon was  Société Athlétique de la Villa Primrose in Bordeaux (1909) . 28 from 21 nations competed in Chicago Marathon . 24 (from 5 confederations) were the number of teams who competed in Chicago Marathon . 5 September 1971 is when Chicago Marathon was founded  . 12 events were there in Chicago Marathon . 1 August was when it was held
Information about Chicago Marathon could be found at www.hardrock100.com