What was the first city to reach a population of one million?

In 133 BCE, Rome became the first city in the world to reach a population of one million people.

Rome has not always been the capital of Italy; prior to the unification of Italy in 1870, the capital city was Florence.

Togas are seen as a popular garment worn by the ancient Romans, but their use was restricted to male citizens who had not been born into slavery.

Rome is the only city in the world that surrounds an entire country: Vatican City is an independent nation-state under papal authority that is located within the city of Rome.