The number of cities in West Africa has grown significantly since 1950, with 41% of the region's population now living in urban areas. A new dataset called Africapolis provides detailed information on urbanization trends in 17 West African countries from 1950 to 2010. This dataset uses various sources like satellite imagery to estimate populations and track changes in urban areas. The data shows that most cities in West Africa have fewer than 100,000 people, highlighting the importance of small cities in the region. Additionally, the dataset includes new measurements of urbanization in Nigeria, offering the most complete information on urbanization in the country to date.