The Flies takes place in the town of Argos in Ancient Greece, sometime in the 12th or 13th century B.C. As we discuss in "In A Nutshell" Sartre is working with an ancient myth rendered many times over in classic Greek theatre. For the purposes of his play, the specific day in question is the fictional "Ceremony of the Dead," which just happens to be fifteen years to the day after the murder of Agamemnon. In other words, this isn't just another day in the ancient Greek neighborhood. Orestes has arrived at a very specific time in a very specific place – the stage is set for some major drama.
You can also think about the specific stage set-up in the three different acts and four different scenes of The Flies. Sartre's stage directions cut right to the chase, so it doesn't take much digging around to see the point he's making with his props and scenery.
Take Act I, Scene i – you've got "a public square in Argos, dominated by a statue of Zeus, god of flies and death. The image has white eyes and blood-smeared cheeks." Similarly, in the throne room of the palace, "an awe-inspiring, blood-smeared image of Zeus occupies a prominent position." The other two scenes of the play are also marked by symbols of the gods – the temple in the second act and the statue of Apollo in the third. The stage set-up reminds us that the gods are a dominating force for the people of Argos. And yet it's the images of the gods – not the gods themselves – that are held up as pillars of authority.