What happened on 14 December?

11 events from the Ever-When timeline, ranked by how much they mattered.

1. 1900 Planck's quantum hypothesis Max Planck proposes that energy is quantised, founding quantum theory - one of the two pillars of modern physics alongside relativity.
2. 1911 Amundsen reaches the South Pole Norwegian expedition is first to the geographic South Pole; beats Scott by 34 days.
3. 1918 Sinn Féin sweeps the 1918 election In the first election of the peace, Sinn Féin takes 73 of Ireland's 105 seats on a pledge to abstain from Westminster and declare a republic — obliterating the old Home Rule party.
4. 1986 The sarcophagus seals Reactor 4 In seven months, under lethal radiation fields, 400,000 cubic metres of concrete and 7,000 tonnes of steel entomb the burnt-out reactor — built by crane operators working from lead
5. 1941 Burma Campaign Long Japanese-British-Indian-Chinese-American struggle in Burma; Kohima and Imphal turned the tide.
6. 1995 Dayton Agreement US-brokered accords end the Bosnian War and partition Bosnia into two entities.
7. 1546 Born: Tycho Brahe Danish astronomer whose meticulous observations made Kepler's laws possible.
8. 2012 Sandy Hook shooting A gunman kills 20 children and 6 staff at a Connecticut elementary school, intensifying America's gun-control debate.
9. 1861 Death of Prince Albert Victoria's husband dies of typhoid; Queen withdraws into seclusion for years; reshapes the monarchy.
10. 1972 Apollo 17 leaves the Moon Gene Cernan lifts off from the Taurus-Littrow valley as the last human being to stand on the Moon — a distinction that has now held for over half a century. The plaque left behind
11. 1895 Born: George VI Reluctant king who steadied the British monarchy through the war years.