Solve today's puzzle and join us for walk in the corn field on a cloudy day. Corn, also known as maize was first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The maize plant is often 3 m (10 ft) in height, though some natural strains can grow 13 m (43 ft). Ears develop above a few of the leaves in the midsection of the plant, between the stem and leaf sheath. Because it is cold-intolerant, in the temperate zones maize must be planted in the spring. Before World War II, most maize in North America was harvested by hand. From the 1890s onward, some machinery became available to partially mechanize the processes, such as one- and two-row mechanical pickers (picking the ear, leaving the stover) and corn binders. Today the combine with a corn head is the modern and preferred harvesting tool.