no-mans-land and the covering positions of the Polish defence lines were composed of Warsaw Ghetto ruins and big open areas of Kercelego Square, Żytnia street and Leszno street. The Home Army was not well enough equipped to withstand a German armoured attack in open field. However, the main positions in the Old Town were densely urbanised and covered with small, narrow streets. Because of that, after initial successes in taking the outer rim, the German advance was halted. However, Germans amassed large numbers of artillery for the constant bombardment of the area behind Polish lines. According to von dem Bach himself the number of guns used in the bombardment was as follows: 220 guns of various calibres 1 heavy mortar Thor 610mm 50 Goliath self-propelled mines 1 company of Nebelwerfer 42/43 1 battery of Wurfgranate of various calibres (ranging from 150mm to 320mm) 4 Junkers Ju 87 Stuka dive-bombers operating from the Okęcie airport The usage of heavy artillery and constant air bombardment (the planes from Okęcie airport needed only five minutes to reach their targets) inflicted heavy casualties on the civilians and destroy the city itself. This aim was expressed in direct orders of Adolf Hitler, Heinrich Himmler and Heinz Guderian. Despite German superiority, both technical and numerical, the Old Town was held until the end of August. However, the situation of both the Home Army and the civilians became critical: lack of food, water and munitions made further defence of the ruins impossible. Several plans to break through the German positions in Ogród Saski park to the downtown and through the northern railroad to Żoliborz failed. On September 2 the defenders of the Old Town withdrew through the sewers. More than 5,300 men and women were evacuated using this way. The front lines stabilised for a short while, but during the upcoming days and weeks the German counter-offensive would recapture Żoliborz and the Old Town, splitting the area held by the resistance into three separate sectors, connected only by underground canals. Sewers and barricades The city sewer system became an important communication network for the insurgents, who used the sewers to move under the areas occupied by Germans, thus allowing contact between surrounded positions (insurgents had almost no radios). Sewers were also used as a means of evacuation of areas that couldn't be defended any longer. Hand-to-hand fighting took place in the pitch blackness, the Germans throwing grenades