What is the scariest suspenseful film you ever saw?

[longship]

16. "The Haunting" (1963)

Saw it with a friend when I was in 9th grade. Could not sleep in the dark for a week.

Then, I read the book, ("The Haunting of Hill House" by Shirley Jackson) and it's even scarier.

No live organism can continue for long to exist sanely under conditions of absolute reality; even larks and katydids are supposed, by some, to dream. Hill House, not sane, stood by itself against its hills, holding darkness within; it had stood so for eighty years and might stand for eighty more. Within, walls continued upright, bricks met neatly, floors were firm, and doors were sensibly shut; silence lay steadily against the wood and stone of Hill House, and whatever walked there, walked alone.

Shirley Jackson "The Haunting of Hill House" first paragraph.

On edit: This is the original version, directed by Robert Wise, not the garbage remake released a few years ago.