What Started the First World War?

World War One was preceded by an unfortunate event. When the heir to the Austrian Empire Franz Ferdinand went to visit Sarajevo, he was murdered. This incident sparked the start of the war as Serbia was blamed for the attack. Austria asked Germany to help defeat Serbia and its ally Russia. Thinking France would get into the mix and that Russia would take a while to gather forces, Germany attacked France first by way of Belgium, who had a treaty with England that England would defend them in a war. As the war played out, Germany and Austria were fought by Belgium, France, Russia, and England.