Safety Last! (1923)
One afternoon in downtown Los Angeles I stopped to watch Bill Strothers, who called himself the Human Spider, scale the sheer walls of a high office building. The higher he climbed the more nervous I grew, until, when he came to a difficult ledge twelve stories up, I had to cut around a corner out of sight of him and peek back to see if he was over the ledge. If it makes me this jumpy, what would it do to a picture audience, I asked myself.
— Harold Lloyd