Fragments from the brain of a man killed by the Mount Vesuvius eruption in the year 79 are smooth and shiny but still contain visible neurons.

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.