From the official history of RAF Bomber Command
27 February 1945
458 aircraft - 311 Halifaxes, 131 Lancasters, 16 Mosquitos - of Nos 4, 6 and 8 Groups to Mainz. 1 Halifax and 1 Mosquito lost. The target area Mainz was covered by cloud and the bombing was aimed at skymarkers dropped on Oboe. No results were seen by the bomber crews but the bombing caused severe destruction in the central and eastern districts of Mainz; this was the city's worst raid of the war. 1,545 tons of bombs were dropped. 5,670 buildings were destroyed, including most of the historic buildings in the Altstadt, but the industrial district was also badly hit. This was the last heavy raid on Mainz.