Santorini volcano

Santorini calder in the Aegean, Greece
Photo by Aster aboard the Terra spacecraft, NASA

Santorini Volcano erupted about 30 cubic kilometers of magma in ~1650 B.C. The ash column is estimated to have risen to ~36 kilometers (~22 miles).  The eruption of such a large volume left a large caldera (the whole image is 18 x 18 km). There has been much speculation that this eruption is the source of the myth of the lost land of Atlantis.  The largest island is There, the next largest is Therasia, and the small islands in the center of the caldera are the Kameni Islands, which are the site of ongoing mild activity.  The most recent eruption was phreatomagmatic eruption in 1950, in which phreatic activity preceded the effusion of lavas.  There may have been a precursor to this island as early as 197 BC, but the current island appears to have started in 46 AD.  Interestingly, it was described by a number of the Roman historians, including Pliny the Elder, who would die 33 years later in the eruption of Vesuvius.