The Zwinger is a building with garden and a famouse Baroque monumentum in Dresden. It served as the orangery, exhibition gallery and festival arena of the Dresden Court. It should have been part of a palace but was not finished after the duke, who commisioned to build it, died. The Zwinger was enclosed when the Neoclassical building called the Semper Gallery was built on its northern side. The name derives from the German word Zwinger (outer ward of a concentric castle); it was for the cannons that were placed between the outer wall and the major wall. Today, the Zwinger is a museum complex that contains the Old Masters Picture Gallery, the Dresden Porcelain Collection, the Armory and the Royal Cabinet of Mathematical and Physical Instruments.