El Mar Menor Nature · San Javier, Mar Menor, Murcia The largest saltwater lagoon in Europe, with a surface area of about 135 km², separated from the Mediterranean by the sand bar of La Manga. It was formed in the Quaternary over a former bay, and the Romans, who called it Belich, used it as a refuge harbour. Photo: Øyvind Holmstad (CC BY-SA 3.0) What to see and do in San Javier