The treaty that officially ended World War I was the Treaty of Versailles , signed on June 28, 1919. It formally ended the state of war between Germany and the Allied Powers. The treaty was negotiated at the Paris Peace Conference and imposed significant territorial, military, and financial penalties on Germany, including disarmament, territorial losses, and reparations payments. Germany was not allowed to participate in the negotiations and was forced to accept the treaty under threat of resumed hostilities. The Treaty of Versailles is considered the most important peace treaty of World War I and was signed in the Hall of Mirrors at the Palace of Versailles
. Before the treaty, the fighting had already ceased with the Armistice of November 11, 1918, which ended the combat but did not formally end the war. The Treaty of Versailles took effect on January 10, 1920
