About an hour's drive from Salzburg, King Lake is known for its clear water. It is known as the cleanest Lake in Germany. The water quality of the lake meets the drinking standard. Since 1909, only electric passenger boats, hand rowing boats and scooters have been allowed to walk on the lake. In addition, the steep cliffs around the lake are known for their clarity, and the Echo Valley is famous for its boat ride. During the tour, the engine will be shut down and the cruise ship will be parked in the lake. The crew will stand by the boat and blow the trumpet to the mountain wall. They can hear the echoes clearly and shroud as many as seven times, which is the experience of visiting King Lake.