League of Nations By Ninap 1920 Vilna failure 1921 Aaland Islands success 1921 Upper Silesia success 1921 The Washington Conference 1923 Corfu failure 1924 Geneva protocool failure 1924 The Dawes Plan 1925 Bulgaria success 1925 Locarno Treaties 1925 The Kellogg-Briand Pact 1926 Germany joins League of Nations Period: 1930 to 1940 The Great Depression 1931 Japanese Government claimed that South Manchurian Railway had been sabotaged by Chinese 1932 Lord Lytton was sent to Manchuria 1934 USSR joins League of Nations 1935 Hoare-Laval Pact