The Castellum theatre and cinema is the new focal point for the redevel¬oped heart of Alphen aan den Rijn. This landmark building defines the public square that runs along the Rhine river, in harmony with the informal character of the neighbouring shops, bars and restaurants. The large hall of 749 seats, second hall of 240 seats and three cinema areas were all made to fit the small site like a Japanese puzzle. The entire programme is ‘packaged’ as a single volume, clad in specially developed corrugated aluminium panels.