Situated by the bank of the river Danube in Novi Sad, the Petrovaradin Fortress was once a defensive stronghold, built in the 18th century. Popular for its series of underground tunnels, the fortress played a key role during the Austro-Turkish wars. The Reversed Clock Tower is one of the iconic landmarks, with the bigger hand showing hours and the smaller hand showing minutes, unlike the conventional clock system. It is made this way for fishermen who can see the time from a distance. Although the Petrovaradin Fortress has seen a fair bit of restoration, large portions still maintain the originality of architecture. The fortress is also the venue of the annual EXIT festival and has hosted some of the biggest names in the music industry such as Guns N' Roses, Snoop Dogg, Fatboy Slim, and The Prodigy.