Fort St. John is considered one of the most impressive monumental buildings of Dubrovnik. Fort St. John also called Port tower and the tower of Mola. Strengthening is located in the southeastern part of the Old town of Dubrovnik and is a complex of fortifications of the city.

For centuries, this attraction was the main defence of Dubrovnik from the sea from enemy ships and pirates. The walls of the fortress in the harbour of the city of flat and steep, and with sea – rounded and sloping.

The fortifications on the site of the present Fort was first built in the mid 14th century, this first Fort is part of the fortress of St. John. Its present form the fortress acquired in the 16th century, when the reconstruction and realignment were United two old Fort and bastions.

Today, the Fort of St. John is a cultural and historical landmark. The fortress houses the Maritime Museum and Aquarium, which is very popular among tourists.

The aquarium is located on the first floor of the Fort. There you can get acquainted with the marine fauna of the Adriatic sea. The second and third floors are occupied by the Marine Museum, which opened in 1872. In the Maritime Museum you can learn about the history of shipbuilding, seafaring and Maritime trade.