In this photo taken on May 20, 2015, Chinese workers travel on the back of a trailer pulled by a tractor on their way to work in Kinshasa, Democratic Republic of Congo. Congos government is bringing in outside experts including officials from the World Bank and the United Nations, to investigate the long-term impact of some $6.7 billion in contracts with Chinese companies that critics have said could exploit the central African nations mineral riches.(AP Photo/John Bompengo)