Bodensee (or Lake Constance) is a lake on the Rhine in Germany at the northern foot of the Alps, and consists of three bodies of water: the Obersee ("upper lake"), the Untersee ("lower lake"), and a connecting stretch of the Rhine, called the Seerhein. The lake is located in Germany, Switzerland and Austria near the Alps and has been swum across by Bruno Doblemann and Christof Wandratsch.
The freshwater lake sits at 395m (1,296 feett) above sea level and is Central Europe's third largest, after Lake Balaton and Lake Geneva. It is 63 km (39 miles) long, and at its widest point, nearly 14 km (8.7 miles). Bodensee was formed by the Rhine Glacier during the ice age. The lake was frozen in the years 1077 (?), 1326 (partial), 1378 (partial), 1435, 1465 (partial), 1477 (partial), 1491 (partial?), 1517 (partial), 1571 (partial), 1573, 1600 (partial), 1684, 1695, 1709 (partial), 1795, 1830, 1880 (partial), and 1963.