Before volcanic eruption in 1600 BC, the island of Santorini (Greece) had different shape than the one we know today. It was almost circular ring surrounding smaller islands inside. Small opening in the outer ring allowed access to the open sea. Ancient Thera had probably the best natural harbor of the all Aegean Islands. It was ideal place for Minoans to develop sea port and big trading center, the second is size city after Knossos on Crete. Ruins of Akrotiri, still mainly covered in volcanic ash, allow to solve puzzles on probably the oldest literate civilization in Europe.