Atlantis is a fascinating legend, but archeologists have never found any evidence for a city with this name. However, the island caldera of Santorini in the eastern Mediterraean Sea was a major seaport of the vast sea-based Minoan civilization of about 1800 BC. And just as Atlantis legend describes a cataclysmic destruction of Atlantis, the town on Santorini was destroyed by a large volcanic eruption in 1650 BC.
The photo shown here (taken by Space Shuttle astronauts in 1983) shows that Santorini is an elongated group of islands, about 15 by 17 km. The islands make a rough ring surounding part of the Mediterranean Sea. The northern half of this bay is the area of an ancient volcano that collapsed about 1390 BC, and, perhaps, the piece of truth in the "Atlantis" legend. This was a huge eruption, with ash falling over parts of Turkey and Egypt.
As with all enduring legends, it is neither proveable or disproveable... but great fun to investigate!
Sources of Information
T.H. Druitt and V. Francaviglia (1992) Caldera formation on Santorini and the physiography of the islands in the late Bronze Age. Bulletin of Volcanology 54, 484-493.