1 of 6 A treaty to protect the world's second largest rainforest in Africa's Congo Basin has been signed by central African leaders and the French president.
2 of 6 Only the Amazon Basin has a greater expanse of tropical forest, and together these regions have been described as the two vital lungs that help the world to breathe.
3 of 6 The Congo Basin forest spans seven countries, which have made a network of protected areas where the resident Ba'aka people are encouraged to use traditional methods.
4 of 6 The rainforest is also home to rare animals, including white rhinos, mountain gorillas, bonobos and elephants. But poachers, bushmeat traders and animal smugglers mean they are under threat.
5 of 6 And the World Wide Fund for Nature warns two-thirds of the forest will disappear in 50 years if illegal logging is not stopped. International pacts have been made to help the forest but monitoring is difficult.
6 of 6 Even if logging companies are only allowed to fell a few of the highest value trees, roads opening up routes into the dense interior, allow hunters and illegal loggers access to the forest.