( CNN ) For the first time in history over half the world 's population live in cities -- more than 54 % of us did in 2014 . Mass urbanization is proving to be `` the single most important transformation '' the world is seeing in the 21st century , according to Jamal Saghir , director of sustainable development at the World Bank , and it shows no signs of letting up . By 2050 , the U.N. predicts 66 % of us will call a city our home . It is generally accepted that cities are the engines of economic growth , and nowhere are these engines firing harder , or populations growing faster , than in the developing world . With burgeoning higher education systems and enviably young workforces , African cities in particular are booming . Commended for their diversity , adaptability and enterprise , investors are taking note . Global auditing firm PwC has now quantified and ranked Africa 's urban hubs in a new report listing the continent 's top `` Cities of Opportunity . '' With the caveat that only one city per country could be assessed , PwC set out ranking locations in terms of infrastructure , human capital , economics and society and demographics . North African cities dominated the top five , with Cairo claiming pole position , followed by Tunis , Johannesburg , Casablanca and Algiers . Analysts cited the age of North African cities as a determining factor , with strong infrastructure across the board , incubating an environment for human capital to thrive . However , sub-Saharan cities registered among the highest in terms of society and demographics , excelling in diversity and population growth , both useful when looking towards future investment . Indeed , the report also offered an alternative ranking , gauging the strongest trajectories in terms of investment . GDP growth , ease of doing business , attracting FDI , middle class and overall population growth all took precedent . Under these criteria , Cairo could only achieve a mid-table ranking and was the only city in the top 10 north of the Sahara . Dar es Salaam , Lusaka , Nairobi , Lagos and Accra made up the top five , suggesting a new generation of African powerhouse economies is waiting in the wings . That being said , one city 's development does not preclude another 's . What is certain is that the battle for economic dominance is on . Read this : Africa 's 10 most prosperous countries . More from Marketplace Africa . Editor 's Note : CNN Marketplace Africa covers the macro trends impacting the region and also focuses on the continent 's key industries and corporations .
U.N. report has sought out the best cities for investors in Africa . North African capitals dominate , but there are signs that sub-Saharan cities will come into their own in the near future .