Greek Polis, in ancient Greece, was typically a social structure or a community structure which consisted of an urban center with a sacred center built on a natural Acropolis. This Acropolis controlled the surrounding territory.
Polis is basically translated into a city-state. Ancient Greece was actually a collection of different polis i.e. city-states. Each polish was completely different than others except that they had a common Greek background.
Every polis was typically just one city but each city had its own political, judicial, legal and religious systems. Hence each polis was apparently an independent state. This independent polis would indulge in trade and international affair with other polls as well as other countries mostly via the sea.
The largest polis or city-state was the Athenian Polis. Other significant policies were Sparta, Corinth, Aegina, Rhodes, Thebes, Elis, Argos etc. There were in total more than 1000 poles in ancient Greece.
All the police had some things in common. Almost all police had a common place where all the citizens would gather to discuss political issues. All citizens only included men. The other common aspect of various police was that they would have a common place for religious worship.
Mostly these places of public gatherings were at the Acropolis. The agora was a marketplace in the policies which was more often than not used for socializing within the community.Hence, Policies were like the building blocks of Ancient Greece.