Following their usual tactics, the Germans had carried out systematic destruction of the houses and had constructed strong underground defenses. The whole city was undermined with tunnels and dugouts, which had been reinforced with concrete, and most of the ruined buildings had been turned into machine-gun emplacements. The effect of the preliminary British bombardment was most demoralizing to the enemy. The first German prisoners taken were in a completely dazed state as a result of the terrific bombardment they had undergone, and other Germans were seen to flee to the rear, deserting their posts as the attack began. The result of this preliminary fire was shown in the speed of the Canadian infantry's advance. The extreme depth reached in the first stage was 1,500 yards, and this was achieved in ninety-three minutes. This new front, taken into conjunction with positions secured previously in the southwestern outskirts of Lens, established an angular line like a pair of shears whose points reached out to the north and south of the city. As the Canadians pushed in on the northwest, a simultaneous advance was started by the troops on the lower blade of the shears, and close fighting began, with the Germans intrenched in their concreted cellars, which were linked up with barbed wire and filled with hundreds of machine guns. The capture of the entire city of Lens was then only a matter of time, as Hill 70 insured the holding of the ground won by the Canadians, German reinforcements being placed under the range of irresistible fire from that dominating height. Among the prisoners taken in the attack were many German lads apparently not more than 17 years of age. The German commander, Prince Rupprecht of Bavaria, made frantic efforts to recapture the lost positions around Lens. The taking of Hill stirred the German high command as nothing else had done on the western front for many months, and a grim battle was waged for several days. On August 16 the enemy came on ten separate times, but they seldom got close enough to the Canadians for fighting with bayonet or bomb. The Prussian Guards participated in the counter-attacks and were subjected to a terrible concentrated fire from the British artillery and Canadian machine guns. Their losses were frightful and all German efforts to retake Hill 70 came to naught, while their hold on the central portion of the mining city became most precarious, as the Canadians consolidated the advantageous positions their valor had finally won. RUSSIAN VICTORIES AND COLLAPSE