The Märjelensee is a calm mountain lake. Originally it was dammed by the glacier and the tunnel served as an overflow. In the meantime, the glacier has melted so much that it is hard to imagine and the lake is being dammed by moraines.
Directly after the tunnel, the small, natural lake is much more idyllic, but the larger reservoir has nothing to hide. A beautiful trail runs along it and it is simply beautiful. If you are doing the Stoneman, remember to stamp your card! Right next to the stamping station, the cozy Gletscherstube invites you to stop for a break.
It used to be a large lake over a kilometer long, today there are several small lakes. The small lakes fit idyllically into the mountains and you can see them very well when walking to the Aletsch. Here is the Märjalen - reservoir, really worth seeing.