JuneJune A major heat wave strikes North America; high temperature records are set and thousands die. The first production model PCC trolley car, built by St. Louis Car Company, is placed in service by Pittsburgh Railways. June 7 The general strike in France is ended by the Matignon Agreements. The Steel Workers Organizing Committee is founded in the United States. June 15 – An army laboratory explodes in Estonia, killing 60. June 19 – Max Schmeling knocks out Joe Louis in the 12th round of their heavyweight boxing match at Yankee Stadium in New York City. June 26 – Focke-Wulf Fw 61, the first fully-controllable helicopter, makes its maiden flight. June 29 – United States Maritime Commission formed