An object that appears to be a screw fixed inside a rock has captured the world's attention since it was found in the 1990s, but the debate rages on about what it really is.
Russian researchers believe the unusual object is 300 million years old, leading some people to claim that it may be proof of a highly advanced lost human civilisation, or even the work of aliens.
However, experts suggest that there may be a more earthly answer – that the ‘screw’ is in fact a fossilised sea creature.
I'd agree with the scientists. ;-) To read more, click here.