Talk about a headache. When Mount Vesuvius erupted, the explosion caused such extreme heat that victims' skulls exploded, their blood boiled and their muscles, flesh and brains were replaced with ash, according to a new study. "New investigations on the victims' skeletons unearthed from the ash deposit filling 12 waterfront chambers have now revealed widespread preservation of atypical red and black mineral residues encrusting the bones, which also impregnate the ash filling the intracranial cavity and the ash-bed encasing the skeletons," the study's abstract reads.