You can find the Banan Cave on the top right corner of the map and the coordinates are G2. You're looking for a stone mountain with lots of trees on top of it and the entrance to the cave is on the left side and once you're inside break the boxes and head down the tight path and you'll find a banana statue with a brown plate / birds nest looking thing and you'll need to throw a banana directly onto the plate to unlock the achievement.
![](https://s2.save4k.ru/pic/TsJJNzhQFTI/mqdefault.jpg)