In the border triangle of Switzerland/Germany/Austria lies the third largest inland lake in Europe, Lake Constance or Bodensee. The lake, which is 64km long and up to 12km wide, is a summer favourite for sailing, swimming or a boat cruise. The Lake Constance cycle path (270km) leads past the lakeside towns of Arbon and Rorschach, and many more. Other popular excursion destinations on Lake Constance include the island of Mainau and the monastery on the Reichenau peninsula, which is a UNESCO World Heritage Site.