It was built by the Knights of St Jean for protection against the growing Ottoman domination in the 15th century. The cross and knight crests, Chapel and animal figures on the gates inside the castle are from this period. The castle, which was defended by different nationalities such as British, French, Italian and German for about a hundred years, could not withstand the Ottoman siege and came under Ottoman rule with the islands Kos and Rhodes. This complex, which can be accessed through seven different doors to the castle inside, has gained a much wider appearance with its hammam and mosque built during the Ottoman period.
Located between two ports, the castle is an area that offers exquisite views of the turquoise blue sea and Bodrum from different angles. It also has the title of being one of the most important Underwater Archeology Museums in the world. This museum, which hosts very important archaeological finds that are definitely worth visiting, includes a very large amphora collection, pieces unearthed from Ottoman and Byzantine shipwrecks, Yassıada, Devil Creek, and Yassıada shipwrecks. The museum is open every day. At the exit, you can sip your coffee in one of the cafes lined up at Bodrum Marina or take a daily charter boat tour to see the different bays of the Bodrum peninsula.