Germany -- unlike its main adversaries -- neither planned nor developed a heavy bomber before or during World War II that was designed to fly long distances and deliver heavy payloads, according to World War II Database. The main aircraft used was the Heinkel HE 111 that was designed for military and particularly blitzkrieg operations. However, the course of World War II led to many bombing operations on European cities. This was facilitated in the early war years by the expansion of Germany and the occupation of much of Europe.
The Soviet Union
The east was the main theatre of war in Europe from the start of Operation Barbarossa by Nazi Germany on June 6, 1941, until the end of hostilities. Most of the materials and manpower of Germany were sent to this region. For Adolf Hitler and the Nazis, the Soviet Union was a source of colonies, inhabited by subhumans and a bitter ideological enemy. No consideration was given by either side for the conventions of warfare or civilian casualties, so the bombing of cities was a normal part of military operations.
Eastern European Cities
Although the Luftwaffe was almost unopposed in the first year or so of the invasion of the Soviet Union, the systematic bombing of cities was not a part of strategic planning. Because of the huge size of the Soviet Union, the Luftwaffe was restricted by range and impact. However, as cities were approached, bombing was used as a part of blitzkrieg tactics. One plan that Hitler had was to erase the three major cities of the Soviet Union -- Moscow, Leningrad and Stalingrad. These were heavily bombed as were others when they came within range of the advancing troops. They included Odessa, Kiev, Minsk and Murmansk.
Other Eastern European cities that suffered from German bombing raids were mainly in Poland and included Lodz, Krakow and the capital Warsaw.
The brief war in Western Europe in 1940 was a blitzkrieg campaign by the coordinated armed forces of Nazi Germany. A part of this campaign was to attack cities by bombing before assault by ground troops. Bombing was also designed to attack strategic targets to inhibit the ability of the opposition to adequately defend them, so many cities were bombed for brief periods. These included Rotterdam and Amsterdam in the Netherlands, Antwerp and Brussels in Belgium, Paris, and later Oslo, Norway.
Following the first planned bombing attack by the RAF on Berlin on Aug. 26, 1940, the so-called "blitz" on British cities began and lasted for 58 consecutive nights. The first and heaviest raids were on London. Coventry, an industrial city in the midlands of England, was also seriously attacked. Strategic and industrial cities in northern England and Scotland were bombed as were most port cities. Those badly hit were Portsmouth, Plymouth, Manchester, Glasgow and Liverpool. However, most British cities were bombed to a greater or lesser extent -- even Belfast in Northern Ireland.