Germany: World War Two
In a sense one can argue that once Hitler took power in 1933 the Second World War was all but inevitable. It is true that few saw that danger as early as 1933. Churchill being a notable exception.
Hitler wanted to see Germany as the dominant European Power, even World Power. He wanted too to be rid of the shame of defeat in The First World War.
As the war drew closer, and he observed the policy of appeasement in Britain and France, he pushed against the Versailles settlement. First the Germans occupied The Rhineland, then came the Anschluss with Austria, and finally the invasion of Czechoslovakia.
Only with the invasion of Poland, made possible by The Ribbentrop-Molotov Pact with Russia, did Hitler turn his attention to the Low Countries, Scandinavia, France, and Britain.
Although, unlike the First War, Britain was forced out of France at Dunkirk, and France surrendered in the summer of 1940.
At this point German success turned into the beginnings of German defeat. Defeated in the Battle of Britain, held in Russia, as a result of launching Operation Barbarossa, and then forced ever backwards towards Germany by The Red Army, held in North Africa and finally defeated there too. The tide of events finally turned with the entrance of The United States into the war, first in North Africa and then in Europe itself. Japan, Germany's ally, was in no position to help as the Americans slowly but surely won the War in The Pacific.
The end of the war in the Allies' favour was now just a matter of time. Yet the Germans resisted right to the end costing so many pointless deaths on both sides.
The war years (1939-45) saw the Nazi regime at its most brutal in Occupied Europe. They committed barbaric acts against both military and civilian populations. The nadir of their barbarism resulted in The Shoah and the murder of 6 million European Jews.
We teach in our schools about this war and Nazism, not from the point of view of victory, but as a brutal lesson of how even in the middle of the 20th century such evil could spawn across our continent and threaten the wider world.