This is a small example on how to use assets in Unity in ways they are not always intended, nothing crazy and you would get much better result by doing a custom asset entirely but you can still get descent results!

Asset Store

The assets used here come from an interior pack which you can get here :!/content/18139

This is a very good asset pack and well worth the price 🙂

Be Creative!

For the watch tower i just use a few of the walls and wood supports. Don’t hesitate to experiment, you can stretch stuff a bit as long as it doesn’t become super obvious that it’s been deformed. Research pictures on what objects / building you want to do and try to rebuild it with whatever you have 🙂