One of the first special effects was the execution of mary queen of scots (1895). inventor and movie maker thomas edison substitued a dummy for the actress. In a short sequence,mary knelt down and put her head on the block as the executioner raised a large axe. When the axe came down,mary's head apparently rolled off the chopping block actually it was the dummy is head.when the audiences saw the scene,they gasp in horror. Since then,filmmakers have used tricks like this to make people see thing that didn't happen in real life