About 100 people actually did walk up the volcano, with the kids (naturally) featured prominently.
It was a glacier but never very large, about six square miles. Some claimed to have drunk pure water from it that they were sure was stored for thousands of years old. That's scientifically true, but only in the same way they drank water a neanderthal peed in. That is the nature of water and recycling.
They predicted all of Iceland's glaciers would be gone in 200 years.