At Africa's heart, there is a vast tropical rainforest - a tangled Jungle, stretching for five and a half thousand kilometres. To survive here is to grasp what rare opportunities you can. But in this endless, primeval world of plants, all is not as it at first seems. Over the millenia, rains have come and gone, rivers have snaked and weaved, an infinite number of trees has grown and fallen, and grasslands have been swallowed and reborn. The forest is not so permanent after all.