Really Big Hole
`This diamond mine in eastern Siberia (Mirny, to be exact) is so deep that the surrounding “air zone… is closed for helicopters” after “a few accidents when they were ‘sucked in’ by downward air flow…” [..]
A now closed diamond mine that measures 1 1/2 km wide 500 m deep. That’s one hole I wouldn’t want to accidently fall into.’
