Overlooked by the Mahale Mountains, this largely untouched national park — accessible only by boat — holds the highest density of primates in Africa, home to around a thousand chimpanzees as well as colobus monkeys, yellow baboons, warthogs and blue butterflies. Walking or sailing are the only means of getting around, allowing for a far more natural and immersive experience of local wildlife. For the more adventurous, climbing Mount Nkungwe, over 2,000 metres high, is an option, while those seeking quieter moments can swim among the countless cichlids of Lake Tanganyika.