A forested mountain between Beppu and Oita where around 1,500 wild Japanese macaques live in two troops, with no cages and no enclosures. Staff put out food at set times to bring them down to the viewing plaza, and the monkeys come and go on their own terms. Visitors are asked not to touch, feed or make eye contact. Buy the plain 520 yen ticket rather than the bundle that includes the aquarium.