Situated on the Mont-Gros plateau, the Observatoire de Nice is a real star in world astronomy. Built (and paid for) by Raphaël Bischoffsheim in 1881, we owe its construction to the combined talents of Charles Garnier for the architecture and Gustave Eiffel for the Cupola. Its 18-metre lens was one of the world's very few instruments to serve for virtual observations of the stars. Two thousand new double stars were thus discovered here in Nice. Today, the Observatory has become one of the world's foremost centers for studying the universe. Guided tour every Saturday at 3 p.m.