Did you know?
Time since introduction of the first mass-produced helicopter (Sikorsky R-4) (75 y) is 40 x Period of Mars's orbit (1.88 y)
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Land used for agriculture in Latvia (2011) (18,860 km^2)
Yes, there's now a book based on these numbers. Oxford University Press: July 2018.
Click here to learn more about it.
Click here for Podcast: Andrew Elliott interviewed for New Books Network.