This postcard depicts the area surrounding the Bodensee, also called Lake Constance. Looking from the North (in Germany) toward the South (Switzerland), the Rhine empties into the lake from the East (on left) and exits to the West (on right) and pours over the largest waterfall in Europe, called Rheinfall. Three countries border on the lake, indicated by the coats of arms: Germany, Austria, and Switzerland. Lake Constance is the second largest (to Lake Geneva) European pre-alpine lake both by area and volume, and the largest lake in Germany. The lake basin was formed by the erosive forces of the Rhine glacier which excavated a 500 m deep valley during its last extension, about 30,000 years before the present. At the end of this glaciation, 15,000 years ago, the lake area was more than twice its present cover, including large parts of the Rhine Valley and both Lake Walen and Lake Zurich. The soil around the Lake is rich in micronutrients derived from this glacial process.