Achaemenid Persian Empire

The Achaemenid Persian Empire under Darius I (522–486 BC) was the world's first superpower, controlling 5.5 million square kilometres—an area larger than the Han Dynasty's maximum extent. It ruled an estimated 44% of the global population at its peak, the highest percentage ever achieved by a single empire. It pioneered human rights via the Cyrus Cylinder, a postal system with 1,800 relay stations, and multicultural governance with 20 satrapies. Its administrative innovations influenced Roman and Ottoman systems for centuries.