Between 1960 and 1962, the combination of economic interest and national pride during the Space Race period inspired scientists of the Soviet Union to plan drilling a “Russian Mohole” whose objective was to reach the Mohorovicic Discontinuity before the American drilling program,” Dean Dunn writing in the book, Science of the Earth.

More on really a big hole in the ground, with shockingly boring (no pun intended) pictures. They drilled for 15 years and reached a depth of 40,226ft. This seems like something only the russians could pull off.