Urbanization is a source of dynamism that can enhance productivity and increase economic integration, a principle evident from the experience of today’s high-income countries and rapidly emerging economies. Indeed, during the Industrial Age, no country has achieved sustained increases in national income without urbanization. If well managed, cities can help countries accelerate growth and “open the doors” to global markets in two ways: by creating productive environments that attract international investment and increase economic efficiency; and by creating livable environments that prevent urban costs from rising excessively with increased densification. By generating agglomeration economies, cities can enhance productivity and spur innovation and national economic diversification. The underlying reason for this is economic density. This report includes the following highlights: growth will remain lackluster in Sub-Saharan Africa in 2016, weighed down by low and volatile commodity prices; addressing growing economic vulnerabilities and developing new sources of sustainable, inclusive growth are key priorities for the region; and Africa’s rapid urbanization offers a potential springboard for economic diversification. But building cities that work will require reforming land markets and urban regulations, and coordinating early infrastructure investments.