Under the leadership of Col. Robert R. McCormick, The Chicago Tribune leases enough time on the Zenith Edgewater Beach Hotel station, WJAZ, to assure program dominance. The Tribune obtains the call letters WGN (World's Greatest Newspaper) from Great Lakes skipper Carl D. Bradley.
That was on March 24th, 1924. On June 1st of that year, the radio station known as WDAP became known as WGN. You can hear WGN today from a good portion of the country at 720 on your radio dial.