By the Hellenistic period, there were pretty much enough Greek temples. Instead of building so many temples, Greek people, started to build a lot of other types of large public buildings. They built many more theaters, and also gymnasia (like our gyms, places to exercise), and, because this was a time with a lot of fighting, also a lot of forts. They built some big impressive tombs for their leaders.
A video of Epidauros’ theater
After Alexander the Great conquered the Persian Empire in the 300s BC, Greek architecture reached all across West Asia and even into India. There was a lot of interest in town planning, and architects planned a lot of new towns with carefully laid out straight streets and public squares. After about 250 BC, however, there was not so much building, because the Hellenistic kingdoms were not rich enough anymore to pay for big public buildings. That didn’t change until the Roman Empire conquered Greece and West Asia in the 100s BC.
Learn by doing: go see a play in an open-air theater
More about Roman Greece
Greek Art and Archaeology (3rd Edition), by John G. Pedley (2002) A lot of good information and is pretty readable. Plus, the author is really an expert in this field.
The Archaeology of Greece: An Introduction, by William R. Biers (1996) Biers writes very clearly and has a lot of good pictures.
The Early Hellenistic Stadium (Excavations at Nemea)
by Stephen G. Miller, Robert C. Knapp, David Chamberlain (2001) By experts, for experts, on their recent archaeological excavations at Nemea in Greece.