My favourite eruption of all time is the Campanian Ignimbrite of 40,000 years ago. It left a caldera eight miles across, mostly under the sea these days in the Gulf of Pozzuoli near Naples, about twelve miles from Vesuvius. On land the main bit still left is the Solfatara crater near Pozzuoli. We scared ourselves to death by visiting it in 2013. It's full of fumaroles and boiling mud pools. San Gennaro, the patron saint of Naples, was beheaded there in the fourth century. You can see his bones sticking out of a big urn in the crypt of the Duomo in Naples. The crater has been closed since 2017 following a terrible accident which killed three members of a family when the ground gave way. The whole area is seismically active and Pozzuoli was largely evacuated in the early 1980s when the ground heaved up by two metres. It went down again but a watchful eye is kept. The Campanian Ignimbrite might have chilled the planet by a degree for a year or two and it's been implicated in hastening the demise of the Neanderthals. Sophia Loren came from Pozzuoli. It's good round there!