World War I began after the assassination of Archduke Franz Ferdinand of Austria-Hungary in 1914. Nationalism, imperialism, militarism, and systems of alliances drew European powers into the war. While attempting to remain neutral, American involvement was inevitable after German U-boats sank American ships and Germany offered Mexico support to take back American lands. The United States declared war on Germany in 1917. After the war, the Treaty of Versailles dismantled Germany's power and created new countries in Europe and the Middle East. Woodrow Wilson proposed the League of Nations but the U.S. did not join.