So.. here's my lil' castle

[Csf91]

Nothing too fancy, but wanted to add water, and found it quite easy to do with the scale Z: 0.

Basically duplicated (shift+D, so not linked) the terrain once shaped, then deleted the bottom vertices in edit mode.
Then, selected all of the faces (it was now a plane with the mountain shape) and hit ctrl - to deselect the borders. Scaled Z to 0 for that.
Extruded 3.5m up and scaled Z for the extruded faces to 0.
As a last step, I’ve flipped normals because they were pointing inwards (ctrl-shift-n with all faces selected in edit mode, make sure all point outwards).

Normals screenshot:

Feedback is very much appreciated!

[NP5]

Nicely done, great idea adding water, almost like a moat.

The keep towers nearly touch in the middle so perhaps some changes in size or proportion is needed?

Nice work doing that bit extra of a scene from the course content.

[Csf91]

Thank you!
Here it is after adding another section of the wall, thought that it might do the trick instead of scaling down the towers (?)

Here you can find my post of the final version, made in the next lesson: My lil' castle.. with flags and turrets :P