tried to move artillery into the city but it could not hit the well-hidden defenders any better than the US soldiers could. Two days later the US again assaulted the city from two sides and this time they fought differently. Not wanting to repeat the mistakes of the 21st, General William Jenkins Worth listened to his Texan advisers. These men had fought in Mexican cities before at the Battle of Mier in 1842 and the Battle of Bexar in 1835. They understood that the army needed to "mouse hole" through each house and root out the defenders in close combat. Worth's men used pick axes to chip holes in the adobe walls of the homes, in the roof of the house from where the soldiers could drop in, or used ladders to climb to the top of a rooftop and assault the Mexican defenders in hand-to-hand combat. The typical assault on a home would include one man who would run to the door of the house and chip the door away with a pick axe under covering fire. Once the door showed signs of weakening, 3–4 other soldiers would run to the door and barge in with revolvers blazing. Worth lost few men on the 23rd using these new urban warfare techniques. Battle of Berlin A Soviet combat group was a mixed arms unit of about eighty men, divided into assault groups of six to eight men, closely supported by field artillery. These were tactical units which were able to apply the tactics of house to house fighting that the Soviets had been forced to develop and refine at each Festungsstadt (fortress city) they had encountered from Stalingrad to Berlin. The German tactics in the battle of Berlin were dictated by three considerations: the experience that the Germans had gained during five years of war; the physical characteristics of Berlin; and the tactics used by the Soviets. Most of the central districts of Berlin consisted of city blocks with straight wide roads, intersected by several waterways, parks and large railway marshalling yards. The terrain was predominantly flat but there were some low hills like that of Kreuzberg that is above sea level. Much of the housing stock consisted of apartment blocks built in the second half of the 19th century. Most of those, thanks to housing regulations and few elevators, were five stories high, built around a courtyard which could