Chungking Mansions, Hong Kong
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Buy your mobile phone in Hong Kong, sell it in Africa

11 October 2013 Last updated at 16:42 BST

In Hong Kong, a 17-storey tower block is playing a central role in driving trade between Africa and China.

One in five mobiles currently used in sub-Saharan Africa is estimated to have physically passed through Chungking Mansions at some point, says the BBC's Juliana Liu.