Ziegenhain, now a district of Schwalmstadt in northern Hesse, was for centuries a fortress town, ringed by ramparts and water and garrisoned rather than settled. Its parade ground survives as an open square at the heart of that old plan, and in the warm months it becomes an outdoor auditorium: a temporary stage, chairs on the gravel, and the earthworks of the fortification standing in for a proscenium arch. Grand opera has been given there in the open air.