It was a conflict on the edge of Europe that started it all: In Sarajevo, then the capital of Bosnia, a student named Gavrilo Princip shot and killed the heir to the Austro-Hungarian throne, Archduke Franz Ferdinand, on June 28, 1914. His wife, Sophie, was also killed. Mere weeks later, Austria-Hungary declared war on Serbia, starting a catastrophic chain reaction. Within just a short time, many nations around the world were enmeshed in the war.