Lake Achen - is the largest and most beautiful of all the alpine lakes in the Austrian Tyrol. The lake is spread over 8 kilometers long and 1-2 kilometers wide. Water Achen is very clean, clear water is okolo10 meters deep, in their qualities similar to drinking water. The depth of the lake at the maximum point -133 m. Since the lake is located in the mountains, the water rarely warms above 20 degrees. Due to the size and the winds Achen is a favorite spot for windsurfing and sailing to skiing.

In winter, the water level in the lake drops to 6 meters, respectively, the size of the lake is constantly changing. At the maximum level of the reservoir can store 66 million cubic meters of water.

Tourism in this region began to develop in 1859 when the railway was built. The first ship "St. Joseph" was launched in 1887, and the second ship "St. Benedict" appeared after only 2 years old, in 1889.

In 1911, a new passenger boat "Stella Maris", designed for 400 passengers and is equipped with a quiet diesel engine, similar to those which were later used in the submarines in the First World War. However, the "Stella Maris" was difficult to maneuver. In 1959, "St. Benedict" was replaced by a modern ship of the same name, and a diesel engine.

Since the lake is located in a conservation area, boats and boats with petrol engines are prohibited. In addition, since the beginning of the 1970s was carried out on the lake swimming sports. Thus, we have created numerous sailing clubs. Currently, the lake often hosts national, European and world championships in sailing.