How American amusement parks first discovered the thrills of “dark rides,” from the Tunnel of Love to the haunted house. Ride designers had to get creative to scare riders in the early days:

“It seems so simple, but Bill Cassidy—the second owner of Pretzel, the son of Leon—told us before he passed away that that was one of the gimmicks that he was most proud of. It was just a spool of thread. It would hang from a rafter in the ceiling, and it would rub up against people’s faces and creep them out. It’s supposed to be cobwebs, I guess, but it wasn’t an actual web. It was just a string, but you couldn’t see it. You weren’t expecting it. That got a real rise out people back then. It seems to me that just about every dark ride I rode in the 1960s had that. If it didn’t come factory-installed, I’m sure the park owners themselves would tack it up.”