The northwestern part of present-day Burkina Faso was populated by hunter-gatherers from 14000 BCE to 5000 BCE. Their tools, including scrapers, chisels and arrowheads, were discovered in 1973 through archaeological excavations. Agricultural settlements were established between 3600 and 2600 BCE. The Bura culture was an Iron-Age civilization centred in the southwest portion of modern-day Niger and in the southeast part of contemporary Burkina Faso. Iron industry, in smelting and forging for tools and weapons, had developed in Sub-Saharan Africa by 1200 BCE. To date, the oldest evidence of iron smelting found in Burkina Faso dates from 800 to 700 BC and form part of the Ancient Ferrous Metallurgy World Heritage Site. From the 3rd to the 13th centuries CE, the Iron Age Bura culture existed in the territory of present-day southeastern Burkina Faso and southwestern Niger. Various ethnic groups of present-day Burkina Faso, such as the Mossi, Fula and Dioula, arrived in successive waves between the 8th and 15th centuries. From the 11th century, the Mossi people established several separate kingdoms.