Theatre of Dionysus built ca. 350 BC This theatre is located in Athens, Greece, just below the Acropolis, part of which can be seen in the upper right corner of this image. Athenians could gather to enjoy many plays here at the sanctuary dedicated to the god Dionysus. http://www.visit-ancient-greece.com/theatre-of-dionysus.html
Theater at Epidaurus - Greece. The theater, dating to the 4th century B.C. and arranged in 55 semi-circular rows, remains the great masterwork of Polykleitos the Younger. Audiences of up to 14,000 were able to hear actors and musicians--unamplified--from the back row of the architectural masterpiece.