Animal skins have been utilized in the lands we now call Oklahoma for thousands of years. Inhabitants used furs for housing, clothing, containers, and as goods in a vast trade network. Burial sites in Oklahoma record copper jewelry from the Great Lakes region, shell beads and conch shells from the Gulf Coast, and turquoise from present-day New Mexico. These examples show the geographical extent of trade within North America until European exploration in the mid-16th century when Spanish conquistadors crossed the Oklahoma Panhandle.