The Day the Earth Stood Still

A spacecraft makes its way towards the earth, it's like a saucer with a rounded, curving girth, when it lands, a man descends, he comes in peace, wants to make friends, and then he's shot, because of difference, we're averse. A robot then appears and shows its power, disintegrating weapons, with its glower, but the alien assailed, gets the giant to curtail, though the sentiment is clear for all to see. It's not long before the foreigner has gone, assimilating, to a world gone wrong, finding out about mankind, finding out how we're so blind, to trajectories that lead to our extinction.

I don't think the message is any different all these years later, just more pertinent.