The Roman Empire
The Biggest City in the World
In 27 BC, the Roman Empire began when Augustus Octavian became the first emperor of Rome. The Romans continued to march into other countries until they controlled an enormous empire. It reached all the way from Britain in the north west to Egypt in the south east.
In AD 117, Rome was the biggest city in the world and the empire covered around 5 million square kilometres (2 million square miles).