WWII
Poland
The American Civil War began with an attack on Fort Sumter, SC.
WW2 began in 1939 when Germany invaded Poland.
The first attack which was at the start of the war was when Nazi Germany and the Soviet Union invaded Poland. World War 2 began in 1939. This caused the war after a couple of years of building up tension between the allies and the Nazis.
World War 2
World war 2 began because Germany invaded Poland
Poland :<
World War II
Poland
Poland.
Poland.
WW2 began with the invasion of Poland by Hitler in 1939, so they didn't "enter" the war. They were the start of the war.