December 17: International Day to End Violence Against Sex WorkersMemorial to victims of the 1970 Polish protests942 William Longsword of Normandy was ambushed and assassinated by supporters of ArnulfI, Count of Flanders, while both were at a peace conference to settle their differences.1948 The Finnish Security Police was established to remove communist leadership from its predecessor, the State Police.1967 Harold Holt, the prime minister of Australia, disappeared while swimming near Portsea, Victoria; his body was never recovered.1970 Polish soldiers fired at workers (memorial pictured) emerging from trains in Gdynia, beginning the government's crackdown on mass anti-communist protests across the country.2010 Arab Spring: Mohamed Bouazizi, a street vendor in Sidi Bouzid, set himself on fire in protest against police harassment, triggering the Tunisian revolution.Rumi (d.1273)mile Roux (b.1853)Willard Libby (b.1908)Alicia Boole Stott (d.1940)More anniversaries: December 16December 17December 18ArchiveBy emailList of days of the yearAbout