Lake of Thun, << toon, >> lies 1,830 feet (558 meters) above sea level in the Bernese Alps in central Switzerland. It is about 30 miles (50 kilometers) southeast of Bern. Formed by the Aare River, the lake is 10 miles (16 kilometers) long and covers 18 square miles (47 square kilometers). An important transport junction occurs at the town of Spiez, where the Simme River enters the lake. A major road and a railway along the lake’s south shore connect the cities of Thun at its west end and Interlaken near its east end. The region’s economy consists mainly of tourism and light manufacturing.