The Nok civilization of Nigeria flourished between 1,500 BC and AD 200. It produced life-sized terracotta figures that are some of the earliest known sculptures in Sub-Saharan Africa and smelted iron by about 550 BC and possibly a few centuries earlier. Evidence of iron smelting has also been excavated at sites in the Nsukka region of southeast Nigeria: dating to 2000 BC at the site of Lejja and to 750 BC and at the site of Opi.