A Man Died in His Bed in Herculaneum. His Brain Turned to Glass.

He was lying in a bed inside a building dedicated to the cult of Emperor Augustus when Vesuvius buried Herculaneum in ash. Nearby charred wood suggests the room reached temperatures as high as 520 degrees Celsius (968 degrees Fahrenheit).

When archaeologists recovered his skull in the 1960s, they found a glassy substance inside it. Testing turned up proteins and fatty acids consistent with brain tissue, along with compounds typically found in human hair oils. No plant or animal source nearby could explain it.

It's the only known example of vitrified organic remains, human or otherwise, ever found anywhere. Vitrification happens when intense heat is followed by extremely rapid cooling; without the rapid cooling, tissue just burns. The heat, researchers say, likely wasn't the hard part. What cooled it fast enough to form glass is, in the original researcher's own words, still a mystery.

A separate study looked at people who sheltered in stone boat chambers along the coast during the same eruption. Their bones showed less heat damage than expected from direct exposure to the volcano's surges, suggesting the chambers' stone walls and the crowd of packed bodies blunted the heat. Rather than dying instantly, these victims may have effectively been baked. Not everyone agrees: the scientist behind the glass-brain finding maintains that surge temperatures inside the shelters were high enough to fracture skulls.

Nearly 2,000 years later, scientists still can't agree on how either death happened, only that neither one was quick.

Read the full story at National Geographic, January 23, 2020

Hot Take: Nearly 2,000 years of study, and the scientists who found this brain still can't agree on how, or even whether, it actually turned to glass. Vesuvius left two separate mysteries in two separate neighborhoods, and neither is solved.