This idea has been done before on this site, but I wanted to resurrect it just for fun. The purpose of this thread isn't to simply make a list of Presidents. Rather your challenge, should you chose to accept it, is to explain another poster's AH list of Presidents or Prime Ministers. Then you put forward your own list for others to explain. For example: one user posts a list of Presidents that includes Donald Rumsfeld as the 41st President - without any explanation of how history changed. The post includes just the list, and nothing else. Your job is to explain how that AH scenario came to be, then post your own original list.