The Kola Superdeep Borehole (, "Kolskaya sverkhglubokaya skvazhina") was a very deep hole dug on the Kola Peninsula in Russia during 1970-1992 and closed by 2008. It was dug in order to learn more about the inside of the Earth. Digging started on May 24, 1970. The work continued until 1992, or 1994. The borehole was kept open until 2005. SG-3, the deepest part of the hole, reached below the surface in 1989. That is the deepest hole ever made and is still the deepest man-made point on Earth.