When we think of the world’s most expensive cities, it’s the traditionally chic European and North American metropolises like New York, Paris and London that usually come to mind. But according to a new cost of living survey by Mercer, an international consulting organization, two of the three most expensive cities in the world for expatriates are in Africa. Sure, usual suspects like Geneva, Moscow and Zurich are on the list, but the vast amounts of natural resources found in places like Luanda, Angola, and N’Djamena, Chad, have triggered a spike in the costs of living there. The survey, which has a number of surprising entries, covers 214 cities around the world and measures the comparative cost of more than 200 items and services in each location, including transportation, food, clothing and housing. Maybe more importantly, the list reflects a gradual shift in wealth from the U.S. and Europe to emerging markets in Asia and South America.