With the help of the Administration des Domaines, Raphael Bischoffsheim (a wealthy banker) acquired a vast property of 35 hectares above Nice on Mont Gros, which he surrounded with a 4 kilometres wall. Between 1879 and 1887, date of the inauguration, fifteen buildings were constructed, the main one sheltered the big equatorial; the famous architect Charles Garnier was in charge of the construction. The dome (24,90 metres in diameter) was conceived by Gustave Eiffel. The big telescope, 18 metres long, was realized by the best opticians, the brothers Henry, and, for the mechanical part, by Gautier. The other buildings sheltered a small equatorial of 9 metres, a coudé equatorial which studies the stellar atmospheres, the double astrographe which looks for comets and asteroids. The 18 metres telescope was for a long time the only one in the world; through it some 2,000 stars have been discovered. In 1962, supervised by Professor Pecker, most of the buildings and instruments were restored. The observatory was con