Apenheul Primate Park opened its gates to the public on 12 July 1971. The ideas of founder, Wim Mager, were considered controversial. Having monkeys and humans walking around without any barriers between the representatives of the two species was unusual and never tried before. The close encounters with the woolly monkeys – one of the few species the ‘experiment’ started with – together with the accompanying stories about deforestation of tropical rainforests should get across better the message that nature conversation is vital for the long-term viability of Planet Earth, according to Wim Mager. The first three years with woolly monkeys, spider monkeys and capuchin monkeys, proved to be commercially successful, which led to a City Council decision to extend the zoological park with gorillas. So in 1976, the Gorilla island was opened – with gorillas that were sourced from the wild. New knowledge and insights about the transmission of disease between (human) primates and human beings led to the decision that no close encounters with gorillas should be possible. Hence, the development of the island enclosure.