In its narrow meaning, a backdrop is a painted cloth hung at the back of a theatre stage as part of the scenery. But we humans use it in a far wider way to indicate the setting against which the action takes place. The action is where the action is, and the backdrop merely serves the function of being appropriate to the action. Without the action taking place now or set up to be enacted, there can be no backdrop. Then one would have to look at things as they are.
People having their photos taken against the backdrop of one of the clocks in the towers of the Musee d’Orsay in Paris