LUMBARDA, Croatia—Archaeologist Mate Parica was examining satellite images of Croatia’s coastline when he spotted something unusual. “I thought: maybe it is natural, maybe not,” said Parica, a professor at the University of Zadar. The image showed a large, shallow area on the seabed jutting out from the eastern shore of the island of Korcula. Parica and a colleague decided to dive at the site and discovered what they believe is a Neolithic settlement from around 4,500 years BC, built on a small piece of land that was connected to the main island by a narrow strip. The pair found the remains of stone walls which had surrounded the settlement, as well as tools and other objects used by the inhabitants. “We found some ceramic objects and flint knives,” he said. Marta Kalebota who runs the archaeological collection in the Korcula town museum, said the settlement’s location was highly unusual. “We …