David Bowie once sang of life in the Underground. He was singing about goblins. Imagine life underneath some of the world's largest lakes. You would be pleasantly surprised at the findings. North America's Great Lakes are the largest system of free fresh water on earth, wielding huge influence on the continent. Over 34 million people live by their shores in some of greatest cities in the world. This groundbreaking program pulls a virtual plug on the huge lakes, using computer-generated imagery to reveal hidden secrets of their human history and changing geological past. Amazing!
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