Iwatayama Monkey Park sits above Arashiyama, reached by a steep but short climb from near the river. At the top, Japanese macaques roam around the viewing area while visitors feed them from inside a hut, reversing the usual zoo arrangement.
The monkeys are the draw, but the view across Kyoto is almost as good. Bring water for the climb and follow the feeding rules; this is still a wild-animal stop, not a petting zoo.