| 1921 | 1936 |
| – New Economic Policy (NEP) in U.S.S.R. | – Start of great purges under Stalin; Spanish Civil War begins |
| 1922 | 1937 |
| – Mussolini gains power in Italy | – Japanese army invades China |
| 1924 | 1938 |
| – Mussolini seizes dictatorial powers | – Kristallnacht marks beginning of more aggressive anti-Jewish policy in Germany |
| 1924–1929 | 1939 |
| – Buildup of Nazi Party in Germany | – Germany occupies Czech lands and invades western Poland; Britain and France declare war on Germany, starting World War II; Soviet Union occupies eastern Poland |
| 1927 | 1940 |
| – Stalin comes to power in U.S.S.R. | – Germany defeats and occupies France; Battle of Britain begins |
| 1928 | 1941 |
| – Stalin’s first five-year plan | – Germany invades U.S.S.R.; Japan attacks Pearl Harbor; United States enters war |
| 1929 | 1941–1945 |
| – Lateran Agreement; start of collectivization in Soviet Union | – The Holocaust |
| 1929–1939 | 1942–1943 |
| – Great Depression | – Battle of Stalingrad |
| 1931 | 1944 |
| – Japan invades Manchuria | – Allied invasion at Normandy |
| 1932–1933 | 1945 |
| – Famine in Ukraine | – Soviet and U.S. forces enter Germany; United States drops atomic bombs on Japan; World War II ends |
| 1933 | |
| – Hitler appointed chancellor in Germany; Reichstag passes the Enabling Act, granting Hitler absolute dictatorial power | |
| 1935 | |
| – Nuremberg Laws deprive Jews of all rights of citizenship | |