Central Powers Collapse

Two key events in 1917 changed the course of World War I: Tsar Nicholas of Russia was forced to abdicate in March and a provisional Russian government was formed, and the United States declared war on Germany in April. In October, Bolsheviks overthrew the provisional Russian government and signed a separate peace treaty with Germany, freeing German troops for the Western Front. Germany then launched a massive last offensive in the West in an attempt to win before large numbers of American troops arrived, though they were ultimately unsuccessful.