An open-air theatre in Tampere, Finland that “tackles the problem of scene setting in the open in a new way. While the audience watches a scene on one side, the new scene is set behind them. When the time comes, the entire auditorium is spun round on a turntable to face the new scene.” Stiknord
The origin of a modern concert theatre can be seen here in a 3D Model of the ancient open-air Theater of Marcellus, Rome - built 13BC. It is basically half a circle: the multi-storey aqueduct model rotated.