While the Adena were building great mounds here, the Great Wall of China was built from 500 to 200 B.C., the Roman Coliseum was built from 72 to 80 A.D., and Confucius, Socrates, and Aristotle lived in the same broad era. Unlike their hunter-gatherer ancestors, the Adena began village life, developed extensive trade routes, grew plants, made pottery to cook and store food, and built majestic burial mounds. Their far-reaching trade networks brought exotic materials, and artifacts such as copper bracelets, ear ornaments, beads, shell beads, mica objects, and copper headdresses may have served as status symbols or regalia used by leaders in public ceremonies. Fabric was made from plant fibers such as milkweed, with fibers thigh spun into yarn by hand and then woven or knotted into cloth, fishing nets, mats, or bags. Adena pottery was generally thick, often tempered with stone to prevent cracking during firing, and was usually plain or cord-marked, though some pieces were tool carved with nested diamond designs; these pottery styles help archeologists date excavated layers. Cultivating plants allowed the Adena to remain in one place and control their food supply, with crops including goosefoot, gourd squash, sunflower, maygrass, amaranth, and sump weed, and sunflower seeds could be made into flour for cakes, mush, or bread or rolled into balls for nourishment during travel.