Over 75 years ago before the start of WWII Mahatma Ghandi sent a letter to Adolf Hitler in an attempt to stop the war.
Friends have been urging me to write to you for the sake of humanity. But I have resisted their request, because of the feeling that any letter from me would be an impertinence. Something tells me that I must not calculate and that I must make my appeal for whatever it may be worth.
It is quite clear that you are today the one person in the world who can prevent a war which may reduce humanity to the savage state. Must you pay the price for an object however worthy it may appear to you to be? Will you listen to the appeal of one who has seliberately [sic] shunned the method of war not without considerable success? Any way I anticipate your forgiveness, if I have erred in writing to you.
Your sincere friend
"My relationship with Maggie Smith; well, she got me the job at Potter, practically. So for anyone who doesn’t know that story, I basically owe everything to Maggie Smith, because I worked with her on David Copperfield and then she came on to Potter as McGonagall and said to the director: "You need to audition this boy." So I kind of owe her everything, so to Maggie I just say my fairy grandmother." - Daniel Radcliffe
Maggie Smith saved the wizarding world