St. Peter's Castle stands on the shore of the bay in central Bodrum and is clearly visible from the sea and the waterfront. The fortress was built at the beginning of the 15th century by the Knights Hospitaller. Local stone was used in its construction, as well as parts of ancient structures, including materials from the Mausoleum at Halicarnassus, one of the well-known monuments of the ancient world.

The castle was built as a fortified point on the coast and over time became an important part of the harbor's defenses. Its layout includes massive walls, inner courtyards, and several towers traditionally associated with different lands of the order, including the English, French, German, and Italian. Carved coats of arms, stone details, and other elements recalling the fortress's knightly past have been preserved on the walls and in the passageways.

In the 20th century, the castle was adapted for museum use, and for a long time it housed the Bodrum Museum of Underwater Archaeology. The exhibitions were devoted to finds from sunken ships and objects raised from the bottom of the Aegean Sea. Even today, the fortress is of interest not only as a defensive structure, but also as a place where archaeological collections can be seen in a historic setting.

For tourists, St. Peter's Castle is appealing for its combination of medieval architecture, views of the harbor, and connection to Bodrum's ancient history. It is easy to include in a walk through the city center: the waterfront, marina, and other well-known attractions are nearby.