Adolf Hitler’s 50th birthday on April 20, 1939 was a national holiday in Nazi Germany. On that day, the largest military parade in the history of the Third Reich was held in Berlin. In total, 40,000 to 50,000 German troops took part in the parade, which lasted about five hours and included 12 companies of the Luftwaffe, 12 companies of the Army, and 12 companies of sailors, as well as the SS. 162 warplanes flew over the city of Berlin.
The grandstand comprised 20,000 official guests, and the parade was watched by several hundreds of thousands of spectators. Features of the parade were large long range air defence artillery guns, emphasis on motorized artillery and development of air defense units. [Source: Wikipedia]