The archipelago may have been first discovered by Norse explorers in the 12th century; the islands served as an international whaling base during the 17th and 18th centuries. Norway's sovereignty was internationally recognized by treaty in 1920, andfive years later it officially took over the territory. In the 20th century coal mining started and today a Norwegian and a Russian company are still functioning. Travel between the settlements is accomplished with snowmobiles, aircraft, and boats.