Oulu is a city and municipality of about 130,000 inhabitants in the province of Oulu and the region of Northern Ostrobothnia, in Finland. It is the largest and most important city in Northern Finland and the sixth largest city in the country. Its population growth rate is almost comparable with that of the Helsinki Metropolitan Area. From being a town known for wood tar and salmon, Oulu has evolved into a major centre of competence in the field of high technology, particularly IT and wellness technology. Other prominent industries are wood refining, paper and steel industry. The University of Oulu is located 6 km north of the city center. Oulu Airport, located in neighbouring municipality of Oulunsalo, is the second busiest in Finland. The best known cultural exports of the city of Oulu are Air Guitar World Championships, Mieskuoro Huutajat (also known as Screaming Men), and the now defunct metal band Sentenced. The Oulu Music Video Festival (originally the host of the Air Guitar Championships) is also a significant event. The annual music festival Qstock has risen to acclaim in the past few years; headlining the 2006 festival were UK's Motörhead.