Three German Army Groups begin the invasion of Poland at 4:45am [10:45 pm 31 Aug in N.Y.-Homer]. Massive strikes by the Luftwaffe destroy vital communications and assembly areas, decimating the Polish air force on the ground. Panzer and motorised divisions make deep penetrations into the Polish defences, using tactics soon to be known as the Blitzkrieg. Officially, the first shots of the war are fired from the 280mm deck guns of the vintage First World War Battleship Schleswig-Holstein. Under the guise of honouring the anniversary of the Battle of Tannenburg, the German Battleship, complete with a hidden cargo of Marine assault troops, was allowed by the Poles to anchor directly off the strategic peninsula of Westerplatte, located at the mouth of the Vistula River in Danzig. At 4:47am, permission was given to the ship to open fire on the island, a strategic point on the Baltic Coast needed to support the troops advancing to the south. Shortly after 4:47am, the ship opened up its massive main guns, firing at near-point-blank range and zero elevation. Needless-to-say, the shells literally pounded the small island, but although the ships guns devastated the target, they inflicted minimal casualties on the Poles stationed within. When the Assault Marines hidden within the Battleship disembarked and launched their main assault on the island, they were repulsed taking heavy casualties. Another assault was launched later in the morning by the Assault Marines after more shelling from the Schleswig-Holstein, but this also ended in heavy German casualties. The Westerplatte would prove impossible to take on the first day of World War 2. Lieutenant Wladyslaw Gnys of 2 Krakow Air Regiment shoots down two Dornier 17 Bombers. These were to be the first German airplanes to be shot down in World War 2.