Mountain Lake, also called Beach with Telephone, was painted using oil on canvas. The telephone was a key image for Dalí during the late Thirties, as seen in his famous Lobster Telephone in 1936. Dalí believed this painting was a premonition of the Second World War. In Mountain Lake, as with The Enigma of Hitler (1936), the telephone can be interpreted as referring to the telephone negotiations between Chamberlain and Hitler to seal the Munich Agreement made in 1938.
The telephone handle is hanging by a crutch, signifying the fragility of the peace that the telephone negotiations have created. To stress this point further, there are snails crawling up the crutch and on to the handle of the phone; Dalí was fascinated with all creatures that have their own shell, with their protected softness and their hidden vulnerability.
The mountains in the background are reflected in the lake beneath the phone to give a double image: the lake can also be seen as a fish with the ripples on it forming the scales and the jagged rock to the left forming a tail. Some have seen the image as phallic, with the solitary rock to the right suggesting a female counterpart.