This viewpoint is only famous on Instagram. That's probably because it's not very accessible for the mediocre tourist. Take the cable car (see link below) up to "Kalktrittli". From there on, the path leads steep up the mountain side, until you reach the final plateau. From there, you should be able to spot the "Muttseehütte", but you turn right and walk in the direction of lake "Limmerensee", what means: south, to a little hill. This is the spot! Enjoy a picknick there and of course the view. If you have the time, stay for the night at "Muttseehütte" to witness sunset. A photography tip besides the famous view: If you look in the direction of sunset, you should be able to witness the golden colours covering the alpine meadows like in the books!