Answer:
The event that happened on June 6, 1944, that changed the tide of the war in Europe was Operation Neptune, that is, the Normandy landings.
Step-by-step explanation:
The Battle of Normandy was the military operation carried out by the Allies during World War II that culminated in the liberation of the territories of Western Europe occupied by Nazi Germany. The operation began on June 6, 1944, better known as Day D, with the Normandy landings; the set of naval operations received the code name of Operation Neptune. An airborne assault carried out by one thousand two hundred aircraft preceded the amphibious landing, which involved five thousand ships. On June 6, one hundred and sixty thousand soldiers crossed the English Channel from England to France and by the end of August the allied troops on French soil were more than three million.