Paris meridian

You are standing near a landmark of scientific history that once placed Paris at the very center of the world map. This is the path of the Paris meridian, an invisible line of longitude that served as France's official prime meridian for over two centuries. In 1667, King Louis XIV ordered the construction of the Paris Observatory precisely along this north-south axis, intending to establish France as the ultimate authority in global navigation and timekeeping. For generations, astronomers used this exact line to perform the complex triangulations necessary to calculate the shape of the Earth, a project that eventually helped define the meter as a unit of measurement.