Caldera SOURCE: http://www.afar.com/places/santorini-greece-thira?context=keyword&keyword_text=thira&location_text=
The caldera is the big, blue bowl of water you see from everywhere in Santorini. It was born when a massive volcano erupted in the 17th century B.C.E. Some say Santorini (ancient Thera) was the home of Atlantis until the volcano brought it to an end. The best views of this stunning natural wonder are from the towns of Fira, Imerovigli, Firastefani and Oia. Choose one of them, and then find a restaurant with a terrace to take in the majestic views.