The deepest, SG-3, reached 12,262 metres (40,230 ft; 7.619 mi) (Needs verification. According to markings written on the borehole, the depth is 12,226 m,) in 1989 and is the deepest artificial point on Earth, as of May 2019. The borehole is 23 centimetres (9 in) in diameter.
