By 2030, ten urban areas are projected to attain "megacity" status, a population of more than 10 million people. Six will be in Asia, where more than half of the population will be living in cities at the end of the decade. But the fastest growing megacities will be in Africa — including new megacities in Dar es Salaam (Tanzania) and Luanda (Angola). Can urban planners and governments in Africa keep pace with this rapid urban growth? We look at the world's upcoming megacities, comparing their current and future estimated populations, to get a sense of how crowded each megalopolis will be in 2030.