The soldiers chiseled over 600,000 cubic meters of stone from the ground -- or the equivalent of one-quarter of the Great Pyramid of Cheops.
"Over the first 60 kilometers, the tunnel has a gradient of 0.3 per thousand," explains the project director. That works out to 30 centimeters per kilometer -- an astonishingly shallow angle of descent.
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From the Upcoming ueue, submitted by Minnesotastan.