Situated within the walls of the St. John Fortress is the Dubrovnik Maritime Museum, which exhibits the most important activity of the former Dubrovnik Republic – maritime trade. This museum houses many atlases, maps, navigational instruments and other important maritime items, which serves to educate the public about the sea traditions of Dubrovnik. Visitors can learn about the history of the Dubrovnik Republic, and how maritime trade was so successful at that time. Various views of the maritime history relating to the larger Dubrovnik region is also on display here, extending from the ancient times to today. Furthermore, the museum houses a library, which deals with research and provides activities for visitors.