At the northern hemisphere it's autumn. After a summer of production, nature is preparing for a resting period, at least in the temperate zone. This is accompanied by magnificent colours, in which red and yellow are the most important tones. But did you ever wonder why European trees colour yellow in autumn, and the predominant colour in Northern America is red? Well, I did. But I never got an answer. Until last week, when I asked this same question on a forum of Pentax-users. And there I was redirected to the site of Science Daily. It has to do with the long gone era of the ice ages. Want to know more? Go here.