Gothenburg (English: ; Swedish: Göteborg, pronounced) is the second-largest city in Sweden and the fifth-largest in the Nordic countries. It is situated by Kattegat, on the west coast of Sweden, and has a population of approximately 580,000 in the urban area and about 1 million inhabitants in the metropolitan area. Gothenburg was founded as a heavily fortified, primarily Dutch, trading colony, by royal charter in 1621 by King Gustavus Adolphus. In addition to the generous privileges (e.g. tax relaxation) given to his Dutch allies from the then-ongoing Thirty Years' War, the king also attracted significant numbers of his German and Scottish allies to populate his only town on the western coast. At a key strategic location at the mouth of the Göta älv, where Scandinavia's largest drainage basin enters the sea, the Port of Gothenburg is now the largest port in the Nordic countries. Gothenburg is home to many students, as the city includes the University of Gothenburg and Chalmers University of Technology. Volvo was founded in Gothenburg in 1927. The original, parent Volvo Group and the now separate Volvo Car Corporation are still headquartered on the island of Hisingen in the city. Other key companies are SKF and Astra Zeneca. Gothenburg is served by Göteborg Landvetter Airport 30 km (18.64 mi) southeast of the city center. The smaller Göteborg City Airport, 15 km (9.32 mi) from the city center, was closed to regular airline traffic in 2015. The city hosts some of the largest annual events in Scandinavia. The Gothenburg Film Festival, held in January since 1979, is the leading Scandinavian film festival with over 155,000 visitors each year. In summer, a wide variety of music festivals are held in the city, such as Way Out West and Metaltown.