In 1942, the Nazis ordered the deportation of all Jews from the Warsaw Ghetto. The Warsaw Ghetto held 400,000 people (30% of the entire population of Warsaw), crammed into a tiny area. In its three years of existence, thousands of Jews died of disease and starvation. Yet despite all, the Jews managed to continue religious and cultural activities in the ghetto. Then on the eve of Tisha B'Av, the saddest day of the Jewish year, the Nazis began the deportation of 265,000 Jews, lasting for a period of two months, to the Treblinka death camp. When the Nazis sought to liquidate the ghetto, Jewish resistance fighters took action, digging hundreds of bunkers under the houses, connected through the sewage system. In the spring of 1943, some 750 Jewish partisans began the Warsaw Ghetto Uprising, killing approximately 300 Germans in one month of fighting.