Geneva 15.7%. Of the agricultural land, 0.3% is used for growing crops. Of the water in the municipality, 0.2% is composed of lakes and 2.9% is rivers and streams. The altitude of Geneva is , and corresponds to the altitude of the largest of the Pierres du Niton, two large rocks emerging from the lake which date from the last ice age. This rock was chosen by General Guillaume Henri Dufour as the reference point for surveying in Switzerland. The second main river of Geneva is the Arve, which flows into the Rhône just west of the city centre. Mont Blanc
History of Geneva icons on one hand and to prohibit the celebration of Mass on the other. This move increased further the flight of Catholics from the city into Savoy territories. Following another unsuccessful invasion of Geneva by Savoy forces in October 1535, which ended in a Savoy defeat at Gingins, the Grand Council decided on February 3, 1536 on the destruction of all castles around Geneva in order not to allow any princes another pretext for invading their city. On May 21, 1536, the Genevans declared themselves Protestant by taking a public oath of allegiance to the Lutheran faith where all residents