Av never head of Lake Grimsel before now and thanks to you on this one which has added new info to my knowledge.
Its quit a beautiful place to behold and am not surprised that it serves as tourist centre as well. The first picture appears like an art work and would only take one to read it the gist to know its actually a technology, this is pure creativity of human mind.
Yes, there is illusion in the image but a real engineering marvel.