The pure white of most of the homes and other buildings on the Greek Island of Santorini is spotted with dashes of color and topped by beautiful old windmills and churches. Santorini is in the Southern Aegean Sea, about 120 miles southeast of the Greek mainland. It lies on the rim of a volcanic caldera, surrounding a central lagoon about 7 by 4 miles in size. The walls of the Caldera are roughly 1000 feet high, and the buildings hug the edge of the top. From a distance the white of all the buildings look like snow capping the rim.