Bourtzi is a small Peninsula that divides the harbour of Skiathos town on the same island in two. Its name Bourtzi probably got from being here in the middle ages the fortress, from which to the present day, unfortunately, only ruins are still preserved.

At the beginning of the 13th century, after the transition of Constantinople into the hands of the crusaders, the island passed into the possession of the Genoese brothers Gysi. They built on a tiny Peninsula on the island of Bourtzi in the Venetian style with battlements and loopholes, very similar to the eponymous fortress in Nafplio. The left and right of the main gate was located watch towers. Today to determine the real height of the walls on the remaining ruins is not possible, but assume that the fortification was quite high and powerful. In the fortress there is a Church of St. George, probably also built by Gysi. In this regard, the fortress was called and as the castle of St. George. The main purpose of the fortifications was to protect from the constant pirate raids. The fortress was destroyed in 1660, when the island was occupied by the army of the Venetian Admiral Morosini.

In 1823, after the liberation of the island from Turkish invaders, on the Peninsula first infirmary. In 1906 in the center of Bourtzi was built elementary school, the construction of which was financed by Andreas Syngros. In 1925 near the entrance to the school was placed a bust of the famous Greek writer Alexandros Papadiamantis, who was born, lived and died on the island of Skiathos.

Today, the picturesque Peninsula of Bourtzi, covered with pine forests, with clean and cool air and stunning panoramic views is a very popular destination among tourists. In the old school on the initiative of the city authorities founded a great cultural centre with well-equipped conference hall and a summer theatre, which hosts theatrical and musical performances.