There are about 8,000 organs in France 1,000 of which are protected by the law of 1913 on historic monuments. During the past ten years, the Architecture and Heritage Division of the Ministry of Culture and Communication has committed a third of its budget for musical instruments to Cavaillé-Coll instruments whose superlative quality bears witness to the evolution of organ building. An average of seven million francs per year has been spent solely on restoring these exceptional organs. Today, about a hundred instruments bearing the name Cavaillé-Coll are protected by the law of 1913. These represent the development of the art and practices of organ building as well as the evolution of music in the XIXth Century.