biggest holes in the earth
The Kola Superdeep Borehole (Russian: ÐºÐ¾Ð»ÑÑÐºÐ°Ñ ÑÐ²ÐµÑÑÐ³Ð»ÑÐ±Ð¾ÐºÐ°Ñ ÑÐºÐ²Ð°Ð¶Ð¸Ð½Ð°, Kolskaya sverkhglubokaya skvazhina) is the result of a scientific drilling project of the Soviet Union in the Pechengsky District, on the Kola Peninsula. The project attempted to drill as deep as possible into the Earth's crust.