Castellar is the name of the former islet situated a few metres off the tip of Llançà harbour. One of the most characteristic features of the town, the islet has had many different uses over the course of history, as testified by the numerous archaeological remains found here. Findings from the Late Bronze Age (10th-7th centuries BC) include pottery shards, decorative objects, burials, etc. Other findings point to the existence of a circular lookout tower, probably dating from medieval times, which was destroyed during the Reapers’ War in the 18th century.
During the Second Spanish Republic (1931-1936), two bunkers were built among the rocks at the top of Castellar Islet, which can still be seen today.