the key events in World War 2 was when the axis power invaded Poland in 1939 this led the the british and the french into fighting the axis. another event took place when hitlers nazis stormed trough Russia in 1941. and ind 1942 benito mussulini lost power.
what are the key events during the civil war
that many people had got killed and also people had to get separated
one of them is the sinking of the Luisitania
pearl harbor
the nuking of japan
world war 2 :P
World War 1 World War 2.
World War I and the Great Depression
World War 1 for example.
the assasination of Arch Duke Ferdinant.
Thats quite a big question considering you haven't mentioned which war. I assume World War 2?
Historically the biggest events could be considered to be World War I and World War II. There are many other major events that have happened in Europe going back over centuries.