
Kola Superdeep Borehole
The Kola Superdeep Borehole SG-3 (Russian: Кольская сверхглубокая скважина СГ-3, romanized: Kol'skaya sverkhglubokaya skvazhina SG-3) is the deepest human-made hole on Earth (since 1979), which attained maximum true vertical depth of 12,262 metres (40,230 ft; 7.619 mi) in...