There is a small mountain in Beppu, Japan, that is the home of several thousand Japanese Macaque monkeys.
Its name is 'Takasaki Yama,' in case you think you might like to go.
It is not far away for the 'jigoku meguri', or literally, "The Tour of Hell," so called for its pits of boiling hot spring pools.
Along with the hell tour, it is a major Kyushu attraction (Kyushu in case you didn't know the southernmost of the four major islands of Japan).
Basically, people purchase monkey food from a machine, and then scramble to throw all the food at the monkeys before the rascals charge them.
You see, as soon as the monkeys notice a tourist buying the food, they begin running at him or her en masse, which undoubtedly must be quite alarming.
The tourist attraction always seems to be popular, but once is probably enough for most people, and once was probably too many for the remainder.
These monkeys are aggressive! In fact, I saw my first non-human purse-snatcher there.
A middle aged woman (she seemed a kindly person from the looks of her) must have had a snack of some sort in her purse because one of the larger male monkeys simply ran right up to her, leaped and skillfully grabbed the bag strap and all (multiple offender no doubt), and ran off into the woods with it.
I'm sure she eventually got it back, though perhaps not in one piece.
There are big signs at the entrance of the mountain warning you not to stare at the monkeys.
Try it and you will intimidate them and eventually you will be attacked.
And they do have sharp teeth.
I didn't see an attack when I was there, but it begs the question: Why do they allow the crazy monkeys to mix with people in the first place?