A huge question mark hangs over what this 300 million-year-old object is.
Russian scientists have been pondering its existence since it was found in the 1990s – with many people believing it to be proof of highly advanced lost human civilisation, aliens or a fossilised sea creature.
It was discovered in the Kaluga region by researchers combing through the site of an asteroid strike.
The ‘screw’ was given its age after a series of X-rays by UFO and paranormal team called the Kosmopoisk Group.
A majority of experts think the object is likely to be a sea creature known as a Crinoid.
Some 600 species of Crinoids are now extinct but the creatures live on in different forms in modern seas. . . .