The Jewish ghetto in Warsaw was formed shortly after the German invasion of Poland. On 15 November 1940 it was hermetically sealed off from the outside world. The ghetto, in which half a million Jews were imprisoned, was the largest of its kind in Europe. In the first two years, thousands died from starvation and exhaustion. Then the deportations to the extermination camp in Treblinka started. In the weeks between 22 July 1942 and 6 September 1942 around 300,000 Jews from the Warsaw ghetto were murdered in the gas chambers of Treblinka. After that, only ten percent of the original ghetto population remained. On 19 April 1943 when the Germans tried to deport the last Jews from the ghetto, an uprising broke out. The Warsaw ghetto uprising was to last for a month until May 1943. Young Jewish resistance fighters had taken up arms against the Nazi oppressors. Their courageous action became a symbol for Jewish resistance during the war, sparking off similar behaviour. Today the uprising in the Warsaw ghetto is remembered worldwide each year on Yom ha-Sho'ah, Holocaust Remembrance Day.