Given the era and state of special effects at the time, like many others, the answer is The Exorcist.
Was 14 and saw it on a Sunday afternoon in NYC (waited over 2 hours on line). Being in a jammed packed theater and the level of angst in the room is something I've never experienced since. Took a bus back to Boston with a friend and ended up cutting through some woods in the dark to get to his house. We both got totally spooked and ran at full speed through the woods (plus the extra 3 blocks to his house).
Was 14 and saw it on a Sunday afternoon in NYC (waited over 2 hours on line). Being in a jammed packed theater and the level of angst in the room is something I've never experienced since. Took a bus back to Boston with a friend and ended up cutting through some woods in the dark to get to his house. We both got totally spooked and ran at full speed through the woods (plus the extra 3 blocks to his house).