The Castle of St. Peter, also known as Bodrum Castle, is a historic fortress located in Bodrum, Turkey. Built by the Knights Hospitaller in the 15th century, it was constructed using stones from the ancient Halicarnassus Mausoleum, one of the Seven Wonders of the Ancient World. The castle served as a strategic defense point against invasions and has a rich history tied to the region. Today, the Castle of St. Peter houses the Museum of Underwater Archaeology, showcasing artifacts from shipwrecks and ancient maritime history. Visitors can explore its towers, walls, and beautiful views of the Aegean Sea, making it a popular tourist destination.