The pattern of bombing in Bulgaria, from a limited raid on Sofia’s railway facilities and the Vrajedna airfield in November 1943 to the final raids in March and April 1944 when the extensive use of incendiaries produced much higher levels of urban destruction, was not an accidental progression. In all the major campaigns in Europe (and in the campaigns mounted in eastern Asia) there occurred an evident escalation the longer the bombing went on and the more uncertain were its results.
