In 300 B.C., Carthage was one of the world’s largest cities with up to 700,000 people living within its walls. The Carthaginian republic was a force to be reckoned with, controlling inconceivable amounts of wealth and land all around the Mediterranean.
However, just over a century later in 146 B.C., Carthage was burnt to the ground by the Romans. The destruction of Carthage was so thorough that many things are still not known about their civilization today. Carthage went from being a major power to literally being wiped off of the map.
A few decades after the annihilation of Carthage, it was Rome’s turn to become the world’s largest city for close to 500 years. Of course, Rome itself would fall by 476 A.D. for a variety of reasons.
And so the title of the world’s largest city would transfer again, this time to Constantinople across the Mediterranean.
The World’s Largest Cities Throughout History
In the grand scheme of history, things change quite fast. As Visual Capitalist's Jeff Desjardins explains, one cataclysmic choice or event can turn even the greatest empire into a heap of rubble. Sometimes the decline of a world-class city is more gradual – and it is over time that it loses its title to another place in a far and distant land.
The following animated map from KPMG Demographics tracks the world’s largest cities from 4,000 BC to today, and it shows how temporary a city’s rise to prominence can be.
(Keep in mind that there is some disagreement by historians over which cities were the biggest in certain time periods.)
The power of industrialization and technology can be seen here. Up until the 1800s, it was almost unfathomable to have a city of more than a million inhabitants.
Sanitation was a major limiting factor, but other issues like transportation and a lack of density also made it a challenge. The Industrial Revolution changed that, and starting in the 1800s you see cities like London, New York, and Tokyo taking the title in an exponential fashion. It caps off with Delhi in 2050, expected to have a whopping 40 million inhabitants by that time.