In 1944, the Polish resistance Home Army (). rebelled against Nazi occupation of Warsaw. This rebellion is known as the Warsaw Uprising () today. The resistance Home Army wanted to free Warsaw from Nazi Germany. The resistance army fought against German troops for 63 days. After that, there was no chance of winning, so they surrendered. German troops killed many civilians in the city. After the uprising, the city of Warsaw was destroyed almost completely. At the time of the uprising, the Red Army was stationed on the other side of the river Vistula, which runs through the city of Warsaw. As of 2021, the question, why these troops did not take part in the fighting, is unclear. Historians have given several theories. 