After the German Invasion of Poland on 1 September 1939 began the Second World War, Warsaw was defended till September 27. Central Poland, including Warsaw, came under the rule of the General Government, a German Nazi colonial administration. All higher education institutions were immediately closed and Warsaw's entire Jewish population – several hundred thousand, some 30% of the city – herded into the Warsaw Ghetto. The city would become the centre of urban resistance to Nazi rule in occupied Europe. When the order came to annihilate the ghetto as part of Hitler's "Final Solution" on 19 April 1943, Jewish fighters launched the Warsaw Ghetto Uprising. Despite being heavily outgunned and outnumbered, the Ghetto held out for almost a month. When the fighting ended, almost all survivors were massacred, with only a few managing to escape or hide.