Germany subsequently invaded Denmark and Norway, the Netherlands, and France, and began bombing Great Britain in preparation for Operation Sea Lion, the planned invasion of the United Kingdom. On 21 June 1941, the day before invasion of the Soviet Union, Himmler commissioned the preparation of the "Generalplan Ost" (General Plan for the East); the plan was finalised in July 1942. It called for the Baltic States, Poland, Western Ukraine, and Byelorussia to be conquered and resettled by ten million German citizens. The current residents—some 31 million people—would be expelled further east, starved, or used for forced labour. The plan would have extended the borders of Germany to the east by . Himmler expected that it would take twenty to thirty years to complete the plan, at a cost of 67 billion Reichsmarks. Himmler stated openly: "It is a question of existence, thus it will be a racial struggle of pitiless severity, in the course of which 20 to 30 million Slavs and Jews will perish through military actions and crises of food supply."