In 1943, the Berlin architect Erich Mendelsohn collaborated with the U.S. Army and the Standard Oil company in order to build "German Village", a set of replicas of typical German working class housing estates, which would be of key importance in acquiring the know-how and experience necessary to carry out the firebombings on Berlin.
Big Week (Sunday, 20–Friday, 25 February 1944) had bolstered the confidence of U.S. strategic bombing crews. Until that time, Allied bombers avoided contact with the Luftwaffe; now, the Americans used any method that would force the Luftwaffe into combat. Implementing this policy, the United States looked toward Berlin. Raiding the German capital, the USAAF reasoned, would force the Luftwaffe into battle. Consequently, on 4 March, the USSTAF launched the first of several attacks against Berlin. Fierce battles raged and resulted in heavy losses for both sides; 69 B-17s were lost on March 6 but the Luftwaffe lost 160 aircraft. The Allies replaced their losses; the Luftwaffe could not.
http://research.omicsgroup.org/index.php/Bombing_of_Berlin_in_World_War_IIhttps://en.wikipedia.org/wiki/Bombing_of_Berlin_in_World_War_II#March_1944_to_April_1945