World War 1 had very complicated beginnings. It all started with Serbian nationalists assassinating Archduke Franz Ferdinand of Austria. Austria wanted to use the assassination as an excuse to declare war, but they were worried about Russian aid going to Serbia. They waited until Germany reassured them that help would arrive should Russia enter the war. When Austria declared war on Serbia, Russia mobilized troops to help the Serbians defend themselves. Germany saw this and declared war on Russia. Because Russia was allied with France, Germany proceed to declare war on France. Britain was allied with Belgium, who Germany attacked to get to France, so Great Britain declared war on Germany. Because all these countries had colonies, those colonies began to fight each other. Years later, the US would enter the war because of incidents such as the Lusitania and the Zimmerman telegram. The war to end all wars had begun.