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