What was the smoking gun that started World War 2?

How did the government mobilize public support for US entry into World War 1? What was President Kennedy's response to the Soviet's putting nuclear missiles into Cuba? Which military commander conquered the most land in his lifetime? Which civil war officer commanded the north Atlantic blockading squadron? How did petersburg va. get its name? Who gave the iron curtain its name? What was king Philips plan if his invasion was a success? What day did Frederick D Gregory die? Which 8 nations possess nuclear weapons? What were periscopes used for in ww1? What was the importance of the d what was the importance of D day? How did WWII people feel when there were bombs and fighting and evacuations and executions? What was the event that started world war 1? What did men wear in 1948? What is another name for the b2 bomber? What are after effects of nuclear war? When was World War 1 and why did New Zealand send soldiers overseas to fight? You want information on alpha company 1st battalion 1st marines 2nd platoon Vietnam 1967 1968? What is a buffalo nickel with a soldier on the other side wearing a helmet? Who led the Mexican fight for independence?