Let's look at some of Buster Keaton's most famous stunts. Many of Keaton's stunts were so dangerous that he himself could have died, so the film crew and his colleagues tried to persuade him to stop doing them.
In the end, all of this was done in a single take.
In the initial shot below, he was supposed to cling to the ledge without falling, but he did fall. So we changed the scene and added a scene where he falls without being able to grab onto the awning.