Kola Superdeep Borehole
The hole was made with different machines at different times. The Soviets started making the hole with the Uralmash-4E. Later, they used the Uralmash-15000. At first, they wanted to get to  below the surface. The machines broke the earlier record for the deepest hole on June 6, 1979. The prior record had been held by the  Bertha Rogers hole in Washita County, Oklahoma, in the United States. The machines got to  below the surface in 1983. Then the Soviet Union celebrated (took special note of) this for about a year without going any deeper. On September 27, 1984, the machine broke at a depth of ; its drill string twisted off and was left in the hole. When the Soviets started to make the hole again, they had to start from .