During World War II, Nazi Germany launched a fierce campaign of air raids against other countries.<\/p>\n
That campaign began in Poland with brutal air raids against the civilian population<\/strong>, a practice that Hitler continued in the Netherlands (with a savage bombing of Rotterdam), France and the United Kingdom. Especially hard was the so-called \"Blitz\"<\/strong>, as the German bombing campaign against the civilian population of the United Kingdom was known in 1940 and 1941, with tens of thousands of victims<\/strong>. Although they initially avoided attacking civilian targets, the Allies responded to German attacks in a reciprocal manner.<\/strong><\/p>\n The British bombing campaign against Germany, begun in September 1941, forced the Germans to build air raid shelters in many cities<\/strong>. The incorporation of the United States into the war at the end of that year led the German people to spend much of their time underground, and even to build hospitals, factories and various underground facilities<\/strong>. Many of those facilities still exist, often forgotten beneath German cities. <\/p>\n
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