1953: British Hear Yeti Whistle

The legend:

In 1953, British explorers on their way to the first successful climb of Everest heard a strange whistling cry; this was attributed to a yeti.


        My only source for this incident at the moment is just three sentences from an article about the "wild men of Everest" published in a 1957 issue of Popular Science. Naturally, this needs to be investigated further before it's trusted.