Overview: We live in a highly complex world, one that requires many different skills and abilities to make our way through it. One of these skills is to look at lines and shapes that we see around us and give meaning to them. This ability to read images is an essential part of our lives. If we didn't have it, life, as we know it, would be impossible; our world would be unrecognizable. But at some point in our ancient past, that's what the world was like — imageless. And then something changed. At some point in our human history, probably about 35,000 years ago, we began to create pictures and to understand what they meant. Archeologist call this period the "creative explosion." But why did people suddenly decide to start creating images of the world around them?