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 were often tensions between Calvin and the city's civil authorities. Calvin also supported the admission into Geneva of Protestant refugees, which some circles strongly opposed. Though the city proper remained a Protestant stronghold, a large part of the historic diocese returned to Catholicism in the early seventeenth century under St. Francis de Sales. Geneva has played a historical role in the spread of Protestantism. In addition to becoming a Protestant state, Geneva in the 16th century also became a kind of welfare state, as a general state hospital was established in 1535 by the wealthy Protestant Claude Salomon. A centralized