Greek architecture originated in Greece and spread during the Roman Empire. There were three main periods: Archaic, Classical, and Hellenistic. The Classical period was the peak, with temples reaching their zenith. Temples were the essential buildings and followed orders like Doric, Ionic, and Corinthian, each with distinguishing column and capital styles. Proportion and harmony were highly valued. Architecture expanded with Greek colonization and Alexander's conquests. Theaters, stoas, and agoras were other common public buildings that demonstrated the Greeks' emphasis on beauty, symmetry, and civic life.