Both The Munich agreement and Hitler's invasion of Czechoslovakia were important fact of cause factors of the World War II. Because these things actually made Hitler ready for World War II and Chamberlain decide to declare war on Germany., sSo it's difficult to choose which one is the biggest cause of the war.
The Munich agreement which Britain giving Hitler Sudetenland was the important affair which caused of World War II because it made other countries opposite opposed to Germany and It was caused by Neville ChamberlinChamberlain, the main character who caused World War II. (WHAT?!?!) When in 1938 Hitler tried to get Nazis in Czechoslovakia and Austria, Czechoslovakia, France and Russia wanted to defend Sudetenland. But Britain (ChamberlinChamberlain.) did nothing even though the anschluss broke the Treaty of VersailleVersailles. Because they thought Germany was punished too much in the Treaty of VersailleVersailles and they didn't want to make a war, it just did nothing and even gave Hitler Sudetenland through persuading other countries.
ChamberlinChamberlain thought Hitler will satisfy on this decision and be back to peaceful Germany. And indeed, Hitler said he willwould not want more territory. But it was lie!
Hitler's invasion of Czechoslovakia was the most fatal cause of World War II, because it made ChamberlinChamberlain decide war on Germany and made other countries know Hitler's purpose. Before this affair, Britain(Britain (ChamberlinChamberlain) was very generous to Germany, even if Germany rearmed and invaded other countries. (Because Britain thought Germany was punished too much in Treaty of VersailleVersailles.) But this affair was the exception. Until this affair, Germany invaded other countries, too. But Itit was for loss of Treaty of VersailleVersailles. For example, the Munich agreement which gave Hitler Sudetenland was caused, because Hitler wanted to get German people in Sudetenland. So ChamberlinChamberlain did nothing but gave...