Benin City, Nigeria — In the back yard of a neighbourhood drinking bar, the clang of metal carries from a small bronze foundry. Swirling smoke rises from smouldering charcoal. A small crucible, half-full with molten bronze, sits atop orange-brown embers. Two workmen pour the liquid bronze into clay moulds buried in the sand using long metal tongs. “We are moulding the statue of a man, organ by org...