There's the Lake Constance, a big lake near the Alps with borders to three countries. The Waymark is located in Bregenz, Vorarlberg, Austria.
Lake Constance is a lake on the Rhine 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.
Freshwater Lake Constance is Central Europe's third largest, after Lake Balaton and Lake Geneva. It is 63 km (39 mi) long, and at its widest point, nearly 14 km (8.7 mi). It covers approximately 571 km2 (220 sq mi), and is 395 m (1,296 ft) above sea level. The greatest depth is 252 metres (827 ft) in the middle of the eastern part (Obersee). Its volume is approximately 10×109 m3 (13×109 cu yd).
The lake is situated in Germany, Switzerland and Austria near the Alps. Specifically, its shorelines lie in the German federal states of Bavaria and Baden-Württemberg, the Austrian federal state of Vorarlberg, and the Swiss cantons of Thurgau, St. Gallen and Schaffhausen. The Rhine flows into it from the south, with its original course forming the Austro-Swiss frontier.
source: [DE] Wikipedia