i'm glad you like the idea!

the theatre is the ancient remnants,partly restored, as part of the acroplis compound, if you haven't been to athens, that is the most famous sight of the city, so it is a must go. they still use the ancient theatre for concerts, theatre, you don't need to book for advance but you might want to know the schedule once you get there, i was there during summer concerts time so lucked out. there are many people sit outside and listen, although it is not as good.