Corn has been cultivated in Mesoamerica since 3000 BCE, even before the first pyramids were built in Egypt. It is still a staple in the area, with the people of Mexico eating some 300 million tortillas a day.

Almost every Mesoamerican town has a tortillaria engaged in the timeless process of turning corn into tortillas.

In one tortillaria in the center of the port city Puerto Vallarta, the men begin preparing the day's production at 3:30 each morning. Their work is heavy: each burlap bag of corn weighs 80 kilos, and while some of the process is automated, the men must move several hundred tons of corn, water dough each week with their hands and backs. The corn is cleaned of impurities, cooked several minutes in nearly boiling water, then put into a reservoir to steep. Once the hulls have loosened, they are washed away with cold water, and the softened kernels, now called nixtamal, are dumped into the molino, the mill, to be ground. What emerges is masa, a fresh-smelling, whitish dough.

The dough is mixed with bagged corn meal, then goes into a conveyor-cooker that produces round, steaming, tasty disks of nutritious food. Smelling the hot tortillas, customers line up to take them home.