Although most of Belgrade consists of buildings from the 20th century, there are also some historical neighborhoods that managed to maintain an old city vibe. One of these is Gardoš, in the Belgrade municipality of Zemun. Arguably, the most prominent features of Gardoš are the picturesque cobblestoned streets that snake through individual residential houses, the incongruously large cemetery, and the Gardoš Tower that emerges from the ruins of the Zemun Fortress.

Built on top of a hill, the fortress granted a wide sweeping view of the Danube and the surrounding area, making it a great military asset. In spite of these efforts, the Ottoman Empire eventually did manage to conquer Belgrade in 1521, but not without fierce resistance from the Belgraders. The Zemun Fortress was, in fact, the place where the last battle took place. Subsequently, paintings of Zemun from the 17th century depict ruins where the fortress once stood proud.  

The original plan of the fortress was square, with four circular towers – one on each corner. Nowadays, only sections of the original walls and parts of three towers remain.  In the centre of these ruins, the Gardoš tower was built in 1896. Damaged during the First World War, the tower was renovated in 1962, but years of neglect followed and by the beginning of the 21st century, it was dilapidated. In 2006, new restoration work began, and after six years, the tower re-opened its doors as an art gallery and exhibition center. Nowadays, the fortress offers one of the best panoramic views of Belgrade. 

It was commonly believed that secret corridors branched off from the underground chamber and connected the Gardoš Tower to nearby forts and bygone military posts. Archaeological studies proved that this was simply a myth, but conspiracy theories subsisted. 

A final word is needed to dispel confusion regarding different appellations.  Although Zemun Fortress technically refers only to the remains of the original fortress, the term is sometimes used to refer to the Gardoš Tower as well, but Belgraders also use the term Citadela to refer to this ensemble. As if this were not sufficient, the Gardoš Tower also goes by the names of Millennium Tower and Kula Sibinjanin Janka.