In the 1936 movie Modern Times, a blindfolded Charlie Chaplin rollerskates around on the fourth floor of an under-construction department store. As he skates backwards and hits the staircase trim, he nearly topples to his death.
By reconstructing the entire scene in CG, this GIF reveals the camera trick–called a "glass shot," as that’s what the painting substrate is–the filmmakers used to pull the shot off and keep Charlie safe:
How’s that for clever?
via Core77
GIF Reveals how Charlie Chaplin Performed a “Dangerous” Stunt with Camera Trickery