Rain forests once blanketed West and Central Africa from Guinea to Zaire. Reduced to 2.8 million square kilometers (1.73 square miles), the remaining forest stretches from Uganda west to Cameroon, and from parts of the Democratic Republic of the Congo north to the Central African Republic. It's known as the Congolese or Congo River Basin rain forest. "The Congo Basin rain forest is still largely intact, and there aren't very many protected areas, but one of them is Dzanga-Sangha," says Dr. Cracraft, explaining why scientists from the museum were drawn to it.