Les Portes du Soleil is a large region of the Alps encompassing thirteen resorts between Mont Blanc in France and Lake Geneva in Switzerland, popular for skiing, snowboarding and other winter sports. The region offers 650 km of marked runs and about 230 lifts in total, spread over 14 valleys and about 400 square miles. Snow dumps over the Portes du Soleil are common and snowmaking ensure that slopes are kept healthy during warmer periods.