A visitor to Greece would have seen different things, depending on which polis they visited. The most famous of the poleis, culturally and politically speaking, was Athens so I will concentrate on that polis.
A visitor to Athens during the Golden Age would have seen a very vibrant cultural scene. They would have seen people watching plays. There would have been dramas by people like Aeschylus and Sophocles and comedies by Aristophanes. They would have seen great feats of architecture like the Parthenon. They would have seen art that portrayed the human form in lifelike and flexible poses.
Along with this sort of thing, they would have seen contradictions in society. They would have seen democracy flourishing. At the same time, they would have seen women enjoying few rights and slaves enjoying none.