Sky Kingdom

In the diamond shop den Sky Kingdom, there is a small secret area to the west of the spawn location, in the gloomy forest area. It is shown in the preview and only flying animals can access it.

Directions
From the spawn point, go to the staircase that is north-west. Keep running straight until you come across the river. Go along the river and stop at the first tree in the right corner. Fly up until you find the floating piece of land.