John, who always likes to seek out extremes, this week dug up the Kola Superdeep Borehole, the deepest hole ever drilled at 12.262 km beneath the Earth.
Although they reached this depth in 1989, drilling actually began 19 years earlier in 1970, when Russia was part of the Soviet Union.
The borehole sits on and under the Kola Peninsula, in Lapland at the very north-west of Russia, and part of Murmansk Oblast (word of the day: oblast, an administrative division or province of Russia and other Slavic countries like Ukraine and Belarus. Present-day Russia has 46 oblasts, as well as various republics and krais, or territories).
You can read more about this Russian marvel at Wikipedia.