Paris is located in northern central France, in a north-bending arc of the river Seine whose crest includes two islands, the Île Saint-Louis and the larger Île de la Cité, which form the oldest part of the city. The river’s mouth on the English Channel (La Manche) is about 375 km downstream from the city. The city is spread widely on both banks of the river Seine. Overall, the city is relatively flat. Paris has several prominent hills, the highest of which is Montmartre at 130m.