Cultural: The Enlightenment philosophy desacralized the authority of the monarchy and the Catholic Church, and promoted a new society based on reason instead of traditions.
Social: The emergence of an influential bourgeoisie which was formally part of the Third Estate (commoners) but had evolved into a caste with its own agenda and aspired to political equality with the clergy (First Estate) and the aristocracy (Second Estate).
Financial: France's debt, aggravated by French involvement in the American Revolution, led Louis XVI to implement new taxations and to reduce privileges.
Political: Louis XVI faced strong opposition from provincial parlements which were the spearheads of the privileged classes' resistance to royal reforms.
Economic: The deregulation of the grain market, advocated by liberal economists, resulted in an increase in bread prices. In periods of bad harvests, it would lead to food scarcity which would prompt the masses to revolt.
This is a hard question that is open to discussion even among historians who specifically study World War 2 as a topic and specialize in it.
The most frequent answers that would probably be given is:
1. Pearl Harbor - with the attack of the Japanese on Pearl Harbor, USA was effectively dragged into the war which may have tipped the odds in favour of the Allies.
2. Stalingrad - the Soviet Union captured a huge German army in Stalingrad. The soldiers from this army were either imprisoned until the rest of the war or died due to hunger. In effect this meant that the German forces lost a whole army on the Eastern front.
3. Normandy landings - the Normandy invasion gave the Allies a foothold on the beaches of Western Europe from where they could invade through the mainland right into Berlin by the end.
It took place during the 1860s
