GORT! Klaatu barada nikto.
Ah, who can forget those immortal words? Well, I guess they're no more words than what that South African impostor signed at Nelson Mandela's memorial. Anyway, they saved Patricia Neal's bacon in one of the best sci-fi films ever, The Day The Earth Stood Still. It was intelligently made and still entertains today.
I decided to post this after watching it again recently, right after seeing another great 1950s production of The War of the Worlds. Made over half a century ago, it has special effects that still hold up. Sound stage scenes not withstanding, I still believe those Martian weapons are cruising through California.
If the story is good and emphasizes the human condition rather than computer graphics, it will always work. Watch both of these classic when you get a chance, before the you-know-who get here.