INmusic festival is Croatia’s biggest international open-air festival. The festival is held annually in June in Zagreb and takes place on Youth Island (Croatian: Otok hrvatske mladeži) in the middle of Zagreb’s Lake Jarun.
The festival was started in 2006 and is usually held over two or three days. It includes several genre-specific stages with internationally renowned indie rock, heavy metal and electronica artists. In 2008 The Times included INmusic among the top 20 European summer festivals.
More info: http://www.inmusicfestival.com/en