Mexico. Corn and squash are plant species domesticated by humans through agriculture. But they would only become staples of the local diet 5,000 years later. Even in the eastern forests of North America, seed crops were already present by 3,000 BC, but serious agriculture did not arrive until 4,000 years later, in 1,000 AD. China follows a similar path: millet cultivation began on a small scale in 8,000 BC on the northern plains as a seasonal supplement to foraging and hunting, but it did not become a staple food until 3,000 years later. These examples provide evidence that the path to agriculture was neither obvious nor linear and inexorable as one might think. On the contrary, Neolithic agriculture was an experiment that could and sometimes did fail.
