Nearly 2,000 years after a young man died in the Vesuvius volcanic eruption, scientists have discovered that his brain was preserved when it turned to glass in an extremely hot cloud of ash.

Researchers found the glass in 2020 and speculated that it was a fossilised brain but did not know how it had formed.

The pea-sized chunks of black glass were found inside the skull of the victim, aged about 20, who died when the volcano erupted in 79 AD near modern-day Naples.

Scientists now believe a cloud of ash as hot as 510C enveloped the brain then very quickly cooled down, transforming the organ into glass.

It is the only known case of human tissue - or any organic material - turning to glass naturally.

"We believe that the very specific conditions that we have reconstructed for the vitrification [the process of something turning into glass] of the brain make it very difficult........

© BBC