While investigating the remains of a meteorite outside of Moscow in 1998, Russian scientists discovered a rock with a screw firmly fixed inside.

Geologist estimate the age of the rock to be 300-320 million years old. Evidence shows that the iron atoms of the screw and the silicon atoms of the rock have in fact spread and fused, suggesting the screw is by no means a recent addition to the rock.

Experts agree the screw was artificially constructed, rather than being the result of a natural process.

Reports of evidence of intelligent life existing on Earth in prehistoric times pop up from time to time. These reports include machined parts such as spheres, screws and toothed wheels, as well as more bizarre discoveries such as manufactured boot, sandal and foot prints embedded in billion-year-old stone.

Researchers claim most of the evidence is now gathering dust in the basements of the world’s most prestigious institutions.