It often seems, to those with only a high school (or even basic university) education in the subject, that mathematics is largely a solved problem. Sure, the thinking goes, there are those arcane and abstruse little corners of irrelevancy with which academics busy themselves, but for the most part we know it all, right? In fact there is a great deal that we simply do not know, and do not understand; and a lot of it is much simpler, and much closer to home than you might think. In many ways our understanding of the subject only really began very recently. Let’s take a brief tour of some of what we don’t know.
Site – http://www.kuro5hin.org