Before 2019 what was Le Grand K?

Question

The communes of Le Lavandou, Cunaux and Sarpouranx in France, the Greek island of Delos, the town of Lanjarón, and the Japanese island of Miyajima or Itsukushima have at times had what in common?

Answer 1

The object which defined the magnitude of the mass of the kilogram
Le Grand K was established in 1889 (replacing two earlier definitions for the kilogram) and stored in Saint Cloud, France; it is a roughly golfball-sized object, 90% platinum and 10% iridium by mass. It was replaced in 2019 by definition in terms of three fundamental physical constants: the speed of light, a specific atomic transition frequency, and the Planck constant.