Letter S of Sunday Stamps gives me the chance to show the stamps of my favourite comic characters: Smurfs!
Belgium has featured Smurfs on stamps often. I recently got these, issued on 29 January 2018, for the 60th anniversary of the blue little fellows.
And I had got, years ago, one of the 7 stamps issued in 2008 for their 50th anniversary.
And also from the UN: