I remember when my son wanted to see this film years back, and he quickly wished he hadn’t. It was so frightening that it made him quite distressed, and it took a while before he could sleep comfortably with the lights on again. To this day, I won't watch it alone in the dark. It’s simply too terrifying. Robert Wise had an incredibly diverse and impressive career as a director, and he clearly knew that what remains unseen can be deeply unsettling. A creative person’s mind will often conjure up something far more frightening than anything shown directly on screen. That technique has mostly disappeared, which is probably why so many horror movies these days are disappointing. You should definitely check this one out. Put it on when it's dark. Make sure you’re by yourself. Turn off the lights and give it a try. I challenge you to do that...

Source on TMDB