Salzkammergut is a lake district in the valley of the Traun River, a significant historical and tourist center of Austria. Salt deposits in the region began to be mined as early as the second millennium BCE, making the area important to Europe ever since. In 1997, the Dachstein mountain and the town of Hallstatt were added to the UNESCO World Heritage List. Stunning landscapes, excellent infrastructure, and picturesque historic towns attract many tourists to the region. In winter, visitors come to Salzkammergut for skiing and snowboarding; in summer, for swimming in its lakes.