World War 1 Causes | Web of Alliances, Nationalism, Militarism, Imperialism, + Assassination of Archduke Ferdinand. In this World War 1 student activity, students learn about the FIVE major causes, including imperialism, militarism, nationalism, the web of alliances, and the assassination of Archduke Franz Ferdinand in Sarajevo, Bosnia. Students learn about the underlying factors that started World War 1, including the complex web of alliances that sparked "The War to End All Wars" to begin. S