Straddling the equator, Gabon’s Ivindo National Park has some of the most impenetrable rainforests and wildest rivers on Earth. The densely vegetated, humid 1,200-square-mile region of West Africa is a haven for apes and monkeys—chimpanzees, gorillas, and spot-nosed monkeys to name just a few. A large natural clearing in this vast forest, called Langoué Bai, is frequented by forest elephants and lowland gorillas that are seemingly unafraid of humans.