1905: Einstein’s special theory of relativity.
1911: Chinese revolution ends millennia of imperial rule.
1914: First World War breaks out. Panama canal opens.
1917: Russian Revolution.
1918: First World War ends; collapse of Austrian, German and Turkish empires.
1923: Discovery of galaxies other than Milky Way.
1928: Discovery of penicillin.
1929: Wall Street Crash heralds Great Depression of 1930s.
1933: Nazis come to power in Germany.
1937: War between China and Japan, till 1945.
1939: Second World War begins.
1943: Colossus, first electronic computer, cracks German codes at Bletchley Park.
1945: Atomic bombs destroy Hiroshima and Nagasaki; Second World War ends. United Nations founded. Cold War begins (until 1989).
1947: India becomes independent.
1949: Communists win civil war in China. Formation of NATO.
1950-3: Korean War.
1957: Soviets put first artificial satellite into space. Foundation of Common Market in Europe.
1960: World population 3 billion.
1961: First manned space flight.
1967: First human heart transplant.
1969: First human landing on the Moon.
1975: End of Vietnam War.
1976: US Viking landers touch down on Mars.
1978: First test-tube baby.
1979: Smallpox eradicated.
1989: Invention of the World Wide Web.
1991: Break-up of Soviet Union.
1997: First cloned mammal.
1999: World population reaches 6 billion.
2003: Human Genome Project completed.
2011: World population reaches 7 billion.
2012: Large Hadron Collider demonstrates existence of the Higgs boson.