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Season 10 Episode 15 | 13m 41s
| Video has closed captioning.
Humanity’s drive to explore our planet is one of the defining characteristics of our species. But exploration only works if you know where you are at any given time. Not so easy when you are out at sea with no visible landmarks and the stars above are in constant motion. So, the key to solving this puzzle is understanding that in order to know WHERE you are, you have to first know WHEN you are.
