This clip explains how World War I came to be a global war after the assassination of Archduke Franz Ferdinand of Austria. Austria-Hungary declares war on Serbia for the assassination, and each country's allies declare war on the opposing countries.
An Austro-Hungarian general advises Emperor Franz Josef I to take punitive actions against Serbia for the assassination of Archduke Franz Ferdinand. Emperor Franz Josef worries about the greater implications of these actions since Russia is Serbia's ally. The general believes that the Austro-Hungarian alliance with Germany is enough to restrain them.
The three world leaders Joseph Stalin, Winston Churchill, and Franklin Roosevelt come together during the Yalta Conference to decide how Germany will be defeated, divided and punished. Each leader has his own special interests, and together they decide on their post-war zones of influence across the globe. The Yalta Conference inadvertently set the rules for the Cold War.