On 12 September 1940 Lascaux was discovered accidentally by four youths. They kept the secret for a few days, then decided to inform their former schoolmaster. Crowds of visitors came quickly: 1,500 during the first week. The abbC Breuil, who had moved to Brive because of the war, came on 21 September and drew up a report which was read to the AcadCmie des Inscriptions et Belles-Lettres on 10 October. From that point on, Lascaux received official recognition. It is quite a large cave, and the decoration starts about 25 m beyond the entrance. All of the chambers and the main galleries are decorated with figures of animals and symbols: over I 50 paintings and about 1,500 engravings are more or less well preserved, but the cave is particularly famous for the remarkable quality of the painted figures in the Hall of the Bulls and in the Painted Gallery (Diverticule Axial). Unlike most palaeolithic decorated caves, the sanctuary of Lascaux has been dated with precision. In fact, the cave was frequented in only one period, about 17,000 years ago. Its porch collapsed some time afterwards, thus sealing in the parietal figures and protecting the traces which the magdalenian artists and visitors had left behind.