What a cool piece! I would advise keeping it in your home for three reasons...
1. Consider the differences in climate between the netherlands and zimbabwe... You can't be sure how it would hold up. While it is unlikely, wind, rain, and cold may damage the external or internal structure of the piece, which you wouldn't want. You would be right to worry about that.
2. While theft may seem unlikely, it can happen anywhere and everywhere. This would have to be your decision based on how much it means to you and how much you trust the area.
3. Vandalism or accidental damage is a risk to anything put in a public place. If the item is so precious to you that it can not be replaced, keep it somewhere you are sure it will be safe.
I understand that you want to honor your parents, but I would advise keeping it in a safe to make sure it is preserved for years to come.