Mauritius may be the safest country in Africa, I think.
And they even have a retirement visa. 18,000 USD in a bank account gets you a 10 year retirement visa, I believe.
Not sure how expensive it is to live there and don't know much about the place other than it may be the safest country in Africa.
Botswana might be the 2nd safest country in Africa. And they have the Big 5 wildlife.