In the 1950s, the use of concrete in building underwent a fundamental change. Through a freer approach to form and surface treatment, architects like Oskar Niemeyer and Kenzo Tange revealed a new design potential and demonstrated how the sculptural qualities of the material could be accentuated. Louis Kahn and Le Corbusier explored the expressive qualities of exposed concrete even more consistently. Key works such as La Tourette reveal the full scope of the material. Walter Schöller