The castle, located on the territory of ancient Halicarnassus, was built in the 15th century under the protectorate of the Order of St. John. Previously, one of the Seven Wonders of the World was located here - the mausoleum of the Carian ruler Mausolus. It suffered several earthquakes and was destroyed in 1402. Subsequently, the crusaders used part of the ruins of the mausoleum as building material in the construction of the castle walls. By 1507, the knights carried away the last sculptures from the ruins of the mausoleum, which decorated the castle walls. By 1522, one of the Wonders of the World was finally dismantled and destroyed. Later, the castle capitulated to Sultan Suleiman and all the fortifications and castles of the Order passed to the Turks, and the chapel was rebuilt as a mosque.
In 1962, the Museum of Underwater Archeology was established in the premises of the former castle. The museum consists of more than a dozen exhibition halls, which showcase the world's oldest shipwrecks. At the expositions, visitors can walk along the models of the decks of ancient ships, examining the objects that were found on them. The process of lifting shipwrecks and artifacts from the bottom of the sea is demonstrated to museum visitors in the form of a slide show.