Built by the wealthy Athenian Herodes Atticus in 161 AD in memory of his wife, the Odeon is a Roman stone theatre cut into the southwestern slope of the Acropolis. Its three-storey facade of marble arches is one of the most striking Roman structures in Greece. The theatre seats around 5,000 people and has near-perfect acoustics.
Unlike most ancient monuments in Athens, the Odeon is still in active use — the Athens Epidaurus Festival runs summer performances here from June to August, with opera, ballet, and classical music under the open sky against the illuminated Acropolis backdrop. Attending a performance here is one of the great Athens experiences. Tickets sell out early; check the festival website well in advance.
The theatre is visible from the Acropolis path but only open to the public during performances. It is worth timing a visit to Athens around one of these nights.