TIL that the deepest hole ever drilled by humans is only about 7.5 miles deep. (The Earth is approximately 7,900 miles in diameter)

http://en.wikipedia.org/wiki/Kola_Superdeep_Borehole



Submitted February 02, 2015 at 10:12PM by SilverChaos http://www.reddit.com/r/todayilearned/comments/2uj3v5/til_that_the_deepest_hole_ever_drilled_by_humans/