note ambrus <p> <strong> Future historians will find that the material characteristic to the era starting now is… </strong> <p> (4000-2001 BC was copper age, 2000-1 BC was bronze age, 1-2000 AD was iron age.) <ul> <li> aluminium <li> plastic <li> oil <li> water <li> carbon dioxide <li> copper again <li> iron again <li> silicon <li> salt </ul> <p> <b>Update:</b> [ramrod] makes a valid point, maybe “uranium” or “hydrogen” should be added as well. <p> <b>Update:</b> appeared as [id://804338]. 734686 734686