c 3,000,000 BC
The main difference between ourselves and most other animals is that we use tools. The oldest known tools, found in Africa, were made more than two million years ago. They are simply lumps of stone that have been shattered with another stone to make a sharp edge for chopping meat or wood. The people who made them would also have made tools from wood, but none have survived.
The best stone for tools was flint. This flint hand axe, from about 1000-5000 BC, was found in Saint Acheul, near Amiens, France. If flakes are chipped off, flint naturally forms sharp edges.