The Kola Superdeep Borehole is the
result of a drilling project on the Kola Peninsula in northwestern Russia. The
deepest borehole in Kola, SG-3, reached 12,262 meters in 1989, and is the
deepest hole ever drilled by geologists, and the deepest artificial point on the
planet. For almost 20 years it was also the longest borehole on Earth, in terms
of measured depth along the well bore, until overtaken in 2008 by 12,289 meter deep
Al Shaheen oil well in Qatar, and in 2011 by the 12,345
meter deep Sakhalin-I Odoptu OP-11 offshore well (off
the Russian island Sakhalin).