Wacken Open Air is an open-air heavy metal music festival. It takes place annually in summer in the village of Wacken in Schleswig-Holstein, northern Germany, 80 kilometres (50 mi) northwest of Hamburg.
W:O:A is usually held at the beginning of August and lasts four days. The festival was first held in 1990 as a small event with about 800 visitors and six local German bands. It is currently considered the biggest heavy-metal festival in the world. In 2011, the festival attracted 80,000 festival visitors and 6,000 personnel for a total of 86,000 attendees.