Causes of ww1
Serbia sent in a assassins in a group called the Black hand.They assassinated the archeduke of Austria. The alliance system pretty much said if you go to war ill help you in the war which left to many different countries joining in the war.Austria-Hungary declared war on serbia. Then russia declared war on Austria-Hungary. Then Germany declared war on Ruussia. Then France declared war on Germany and Austria-Hungary. Later Britain joined France and Russia. This big war was called ww1