World Travel City Photography

Keith Hopkins estimates that ancient Rome had a population of about a million people by the end of the 1st century BC, after growing continually during the 3rd, 2nd, and 1st centuries BC. Alexandria's population was also close to Rome's population at around the same time, the historian Rostovtzeff estimates a total population close to a million based on a census dated from 32 AD that counted 180,000 adult male citizens in Alexandria. Similar administrative, commercial, industrial and ceremonial centres emerged in other areas, most notably medieval Baghdad, which according to George Modelski, later became the first city to exceed a population of one million by the 8th century instead of Rome.
While David Kessler and Peter Temin consider ancient Rome to be the largest city before 19th century London, George Modelski considers medieval Baghdad, with an estimated population of 1.2 million at its peak, to be the largest city before 19th century London. Others estimate that Baghdad's population may have been as large as 2 million in the 9th century.
Agriculture was practiced in sub-Saharan Africa since the third millennium BC. Because of this, cities were able to develop as centers of non-agricultural activity. Exactly when this first happened is still a topic of archeological and historical investigation. Western scholarship has tended to focus on cities in Europe and Mesopotamia, but emerging archeological evidence indicates that urbanization occurred south of the Sahara well before the influence of Arab urban culture. The oldest sites documented thus far are from around 500 AD including Awdaghust, Kumbi-Saleh the ancient capital of Ghana, and Maranda a center located on a trade rout between Egypt and Gao.
In the Late Roman Empire, cities in Late Antiquity underwent transformations as the urban power base shrank and was transfered to the local bishop. Cities essentially disappeared, earliest in Roman Britain and Germania and latest in the Eastern Roman Empire and Visigothic Spain.