Evidence of African copper mining and smelting
https://www.smithsonianmag.com/smart-news/national-museum-of-african-art-removes-benin-bronzes-from-display-affirms-commitment-to-repatriation-180979037/?utm_source=smithsoniandaily&utm_medium=email&utm_campaign=20211110-daily-responsive&spMailingID=45921483&spUserID=OTE5NDcwNzM1NjY3S0&spJobID=2121174366&spReportId=MjEyMTE3NDM2NgS2