“A meridian? Right here, in an industrial harbor?” you might ask. Yes, indeed! What you see before you, this unassuming pyramid-like structure, is more than meets the eye. This is the Pyramide von 1810, also known as the Mire, and it once marked a crucial point in geographical history: the Mannheim Meridian. Let me take you back to the 19th century, when Mannheim held a position of scientific importance. Before the global agreement on Greenwich as the prime meridian, every land had its own system. The Mannheim Meridian, established at the Mannheim Observatory, served as the zero longitude for the Grand Duchy of Baden.
The Pyramide von 1810 played a vital role in this system. It acted as a back sighting point for the meridian line passing through the observatory. By aligning telescopes with this precisely positioned marker, astronomers could make accurate observations and calculations. However, the industrial development of Mannheim at the turn of the 20th century necessitated a shift in location for the Pyramide. The construction of the Industriehafen (industrial harbor) meant the original meridian line now ran directly through the planned Kaiser-Wilhelm-Becken. To preserve this historic marker, the Pyramide von 1810 was moved from its original location, which would lie submerged in the harbor basin today.
While it no longer sits on the Mannheim Meridian, the Pyramide von 1810 stands as a testament to Mannheim’s scientific legacy and a tangible link to a time when the world looked to this city for accurate measurements of the heavens and the earth.