The thesis deals with the study of all the fortresses of the city of Šibenik: St. Michael, St. Nicholas, St. John and Barone Fortress. Each of them is elaborated through five thematic points: the historical circumstances related to the construction of the fortresses, their form, the archeological researches conducted, their state before the renovation and the revitalization process itself. Throughout history the Fortress of St. Michael was a key point of defense of the city of Šibenik, and also provided refuge for its inhabitants during the tough times, it represents the main point of the city's formation, while in recent times it is often called the center of cultural events, especially related to the world of music. Fortress of St. Nicholas is an example of the military Venetian fortification construction dating back to the 16th century, and its peculiarity lies in the fact of being isolated as an independent fortification at sea. An extremely important part of the fortification system of the city of Šibenik, especially during the 17th century, are fortresses St.John and Barone. They both played an important role in the defense of the city against the Ottoman Empire in 1647. Today, after being revitalized, both fortresses represent an important example of how fortresses could be renovated, how they can be given the new spirit, and how they can become one of the main tourist attractions of the city of Šibenik.