Santorini volcano has erupted 11 times so far, but it is believed that ~1630 BC eruption, which was one of the most explosive in history, created the huge Caldera that you can see. At the same time, previous island Strogili (round) collapsed 500m in the big blue of Aegean Sea. There is a theory that this eruption, also called Minoan eruption, indirectly affected the disappearance of Minoan civilization on the island of Crete, by creating a gigantic tsunami. Minoan civilization was considered to be the most culturally advanced society of that time. Visit Santorini Greece Virtualy before going there.

http://www.santorini360hotels.com/landmarks/nea-kameni/nea-kameni-volcano