One might assume the most admired architecture would be the best built. This was generally true in the past, but in the twentieth century, when new materials and new aesthetic theories often drove architects to cavalier experimentation, even celebrated architects fell short. When designing the Centre Georges Pompidou in Paris, Renzo Piano and Richard Rogers turned the building literally inside out. Previously hidden elements such as pipes, ducts, and elevators were exposed to view – and exposed to the elements. The result might have been foreseen: after only twenty years, the building was closed for a two-year renovation. Although the authorities maintained that the unexpectedly large numbers of visitors necessitated the renovation, much of the budget was spent on refurbishing the facade.