Many times when walking the picturesque Promenade Du Lac (between the Jardin Anglais and the Jet d’Eau), I have looked out over the water and seen two lumps of stone jutting out of the water. Each time I, and anyone else I know, have wondered: “what are those doing there, sitting in the way of water traffic?”
It turns out that these are the famous “Pierres du Niton,” aka Neptune’s Stones. Legend has it that the giant Gargantua was throwing rocks from the Salève after an unsatisfying party…
The really interesting part of the stones, besides mythological curiosity, is that the smaller of the two is the official landmark of all Swiss cartography. That’s the actual Pierre du Niton; the larger one is the Pierre Dyolin.
In fact, the Pierre du Niton has a graduated metal plaque set by the engineer Guillaume-Henri Dufour to define the average height of the Léman lake. Named the “Repère Pierre du Niton,” or reference stone of Neptune (RPN), this plaque fixes Geneva at being 373.6 metres above sea level.
Funny story: originally set to 376.86 m in 1820, the measurement was dropped by 3 metres after a recalculation. So, all pre-1902 maps of Switzerland and neigbouring France differ from modern ones.
This is a fun piece of Geneva (and West European) trivia, and always a good story to share!