By the 10th day I couldn't stand properly and I drifted along the edge of a larger river I had found.

BBC: Juliane Koepcke: How I survived a plane crash

Local economies also suffer when villagers can't sell their grain or eat the crops planted along the river because the water is so polluted.

CNN: Economic miracle, environmental disaster

People who live along this part of the Congo River hope that their Osama won't be on the loose for as long as the al Qaeda leader has been.

NPR: Congolese Hunt 'Osama' the Hippo