Did you know? Depth of the Mponeng Gold Mine (South Africa) (3.9 km) is 25 x Height of Cologne Cathedral spires, Germany (157 m)
Height of the Empire State Building (NYC) (381 m)
/fact/height-of-the-empire-state-building-nyc
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If this was a standard unit ...
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.