Mire du Sud

The Mire du Sud is a four-meter-high stone obelisk standing in Parc Montsouris that acts as a silent witness to a time when Paris, not Greenwich, was the center of the world's maps. Topped with a perforated cylinder, this monument was placed here to calibrate the delicate instruments of the Paris Observatory, which sits directly on the city's historic meridian line. Throughout the seventeenth and eighteenth centuries, French astronomers used this precise north-south alignment to define the prime meridian, creating a standard that dictated global navigation and timekeeping for over two hundred years. Although it was originally erected in the gardens of the Observatory in eighteen hundred and six, it was later moved to this park, where it now serves as a grounding point for the meridian that defined the very birth of the metric system.