Explanation: One of Hitler's reasons for invading Europe was to get more Lebensraum, or Living Space, Breathing Room, etc.
Answer:
The Silk Road extended approximately 6,437 kilometers (4,000 miles) across some of the world's most formidable landscapes, including the Gobi Desert and the Pamir Mountains.
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They got to know with the photographs from the U - 2 spy plane.
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