This large amphitheatre was built in AD 161 by wealthy Roman Herodes Atticus in memory of his wife Regilla. It was excavated in 1857–58 and completely restored in the 1950s.
The Athens & Epidaurus Festival holds drama, music and dance performances here in summer, and occasionally there are blockbuster pop concerts and other events.
When you're visiting the Acropolis site, the path leads west from the top of the Stoa of Eumenes, and you can peer down into the odeon from above. From this vantage, it looks positively intimate, though it seats 5000 people.