http://agathe.gr/democracy/the_ekklesia.html
The Ekklesia (Citizens' Assembly) All Athenian citizens had the right to attend and vote in the Ekklesia, a full popular assembly which met about every 10 days. All decrees (psephismata) were ratified ... As a rule, the Ekklesia met at its own special meeting place known as the Pnyx, a large theater-shaped area set into the long ridge west of the Acropolis. ... The natural hill slope was used to form an auditorium, and there was a retaining wall at the bottom which supported the terrace where speakers stood.
