Petrovaradin Fortress is an 18th century fortress located on the right bank of the Danube river in Novi Sad, in the province of Vojvodina, Serbia.

The cornerstone of the present-day southern part of the fortress was laid on October 18, 1692, by Charles Eugène de Croÿ. Petrovaradin Fortress has many underground tunnels as well (16 km of underground countermine system).

The fortress was put under national protection in 1948, and in 1991 it was proclaimed a cultural heritage property, a cultural and historical complex of great importance.The Petrovaradin Fortress, exceptional work of the 18th-century fortification engineering, is one of the largest, most complex and best preserved artillery bastions in this part of Europe. It spreads over the northern slopes of Fruška Gora, on the right bank of the Danube. With the apex of 125 m above the sea level, it has the dominant position in the southeastern part of the Panonian Plain. It covers the area of over 100 ha, has a 5200-meter-long outer defence line and a complex system of underground military galleries with mine and listening tunnels, distributed at four levels, with 16000 meters of the total length. Being the last in the series of fortifications using all the advantages of the exceptional geostrategic position, unique in style and concept, it unifies the coherence and monumentality of the military architecture with the natural environment.

Petrovaradins fortress was completely demilitarized in the mid-20th century and proclaimed for a historical monument. It was placed under the protection of the state and assigned to civilian use. At the fortress there are the Museum and Archive of Novi Sad, hotels and restaurants, studios and galleries of artists, academies of art, astronomical observatory, planetarium and many other facilities.

Monumentality of the Fortress at the rocks and the Danube at the base contributed that many call Petrovaradin fortress “the Gibraltar of the Danube.”

Exceptional natural position of the Petrovaradin rock has always been an inviting place for settlement.

EXIT festival is an annual summer music festival that has been held at the fortress since its inception in 2001. Since then, it has grown from the biggest festival in South-Eastern Europe, to one of the biggest in Europe.