We don't know the identity of the experimenter or experimenters in the Acheulian culture in Africa who discovered how to start, control and use fire about 790,000 years ago. But their mastery of rapid oxidation was one of the most important developments that sustained the survival and spread of humanity, according to Nira Alperson-Afil, a member of an Israeli archaeological team that found the earliest evidence of human ability to make and control fire at will [source: Hebrew University of Jerusalem].
The invention equipped early humans with a scary deterrent -- flaming torches -- to protect them and their vulnerable young from predators. It also provided a source of warmth that helped them to survive temperature downturns. In addition, the ability to cook animal flesh and vegetation increased food choices for humans and helped them to avoid malnutrition. Perhaps more than any other invention, fire was the breakthrough that enabled humans to multiply and spread across the planet's surface.
Today, we've progressed beyond gathering around the campfire and gnawing hunks of charred mammoth haunches, but the ability to burn fuel remains a crucial part of our continued existence.