4137 / Mass (Kilogram):Safe with the Ur-Kilo at BIPM in SЏvres bei Paris: EUROPA, FRANKREICH, HAUTS-DE-SEINE, SEVRES (SEVRES, FRANCE), 11.10.2006: Kilogram, SI base unit of mass. Inside a safe in the basement of the Bureau International des Poids et Mesures BIPM in Sevres near Paris, France, the International Prototype Kilogram `K` rests safely protected by 3 glass covers. In a little ceremony once every year, the safe is opened for eyeball inspection of `K` and its official copies. The 3 keys to the safe are kept by the BIPM`s director, the head of the French National Archive, and the president of the CIPM. Since it was made from a platinum-iridium alloy in 1883, `K` defines the kilogram worldwide. - Marc Steinmetz / VISUM - Keywords: France, Paris, Sevres, Bureau, International, des, Poids, et, Mesures, BIPM, science, physics, metrology, base, unit, international, system, of, units, SI, measure, measurement, metrical, standard, accurate, accuracy, prototype, safe, strongbox, basement,