Period 6

Europe

1914 - 1918

1917

1917

1919

1919

1947 - 1991

Asia

1915

1937

1939 - 1945

1945

1947

1950 - 1953

1965 - 1973

1973

North America

1929

South America

1959

1962

Africa

1928

1957 - 1975

1994