After passing through a dark shaft in September 1940, four teenage boys entered an underground chamber filled with wondrous drawings—hundreds of figures of animals, such as horses and deer, and other markings. What must they have thought on first seeing such an array of fantastic imagery from our forbears?

Lascaux Cave, located near Montignac, France, contains more than 2,000 paintings and engravings, which date to some 15,000 or more years ago. The site offers a spectacular example of human creativity, to be sure, but it is far from the first. Still, such a high level of artistry and ingenuity were a long time in coming for our species—as scientists are only now beginning to fully appreciate.

You will learn in our cover story, “The Origins of Creativity,” by Heather Pringle, that “although our human lineage emerged in Africa around six million years ago, early family members left behind little visible record of innovation for nearly 3.4 million years”—probably at least partly because tools or any such items were from wood or other plant material. Stone tools eventually materialize in the archaeological record but hardly change in design for more than a million years.

Most researchers have pointed to the Upper Paleolithic, around 40,000 years ago, when Homo sapiens started adorning cave walls with images of Ice Age animals and forging inventive beaded designs and other innovations, as when the early spark of creativity finally caught fire—yielding the kind of rapid-fire innovative thought that characterizes our species today. But rather than emerging suddenly, relatively recently in our evolutionary history, our creative powers appear to have developed over hundreds of thousands of years, as various biological and other factors came together. In her article, which begins on page 36, Pringle describes the fascinating detective story behind unraveling these lines of evidence.

It's a good thing we evolved ingenuity because we'll need it to combat some of the pressing challenges that we cover elsewhere in the issue. Consider the unpleasant prospect of “The End of Orange Juice,” which senior editor Anna Kuchment describes in her feature, starting on page 52; citrus trees are under a global attack by a bacterial infection. In “New Threat from Poxviruses,” beginning on page 66, Sonia Shah writes about the worrisome cousins of smallpox, monkeypox and cowpox. These are certainly serious matters, but our best hope remains with humanity's most innovation-enhancing invention: science.