Which river flows through Paris?

The Seine, and Paris exists because of a particular feature of it - the Ile de la Cite, an island that made the river crossable and defensible. The Romans found a settlement already there and called the place Lutetia; the city's motto and coat of arms are a ship, with the line that it is tossed by the waves but does not sink.

The river runs through the city in a long curve, and everything is numbered from it. Paris addresses are ordered by distance from the Seine, and the arrondissements spiral outward from the centre like a snail. The Left Bank and Right Bank are defined facing downstream, which is why the Left Bank is in the south.

It floods, and the city keeps a specific measure of it. A stone soldier called the Zouave on the Pont de l'Alma has been the unofficial flood gauge since 1910, when the water reached his shoulders and much of Paris moved about by boat for weeks - a flood of that size is expected roughly once a century and the last one was 115 years ago, which is why the city's flood planning is a live and slightly nervous subject.