The world is fuelled by gold. For centuries, it has been plundered for political influence and used to forge empires from the ground up. Societal status is determined by it, and power is extracted from it. Today, it is embedded in our mobile phones, allows humans to reach space and furthers medical innovation. Photographed across four years and four continents, The Canary & The Hammer, the new publication from photojournalist Lisa Barnard, shows how our dependence on this precious metal was born, and how it still remains the most valuable commodity today.