They call the municipal divisions of Paris what we call “wards” or “boroughs” by a word which may be clumsily translated “aroundments” (arrondissements) ; and they are numbered. Upon a denuded map of Paris they form the shell of a snail. The innermost divisions, which are the oldest, are the smallest. But the 20th and final one is not, as it logically should be, the largest; that honor belongs to the 15th, which occupies eighteen hundred acres southeast of the Eiffel Tower.
Around and around you go I suggest on the map rather than in reality if you want to follow the growth of Paris. Beginning in the 1st Arr., you will have to cross the Seine twice to reach, in its order, the 9th Arr., where the Opéra is.
Then, if you keep on, you will have further to go to get from one arrondissement to the next, and you will again cross the river twice. On your third and last turn you will find yourself in the 20th Arr. and near the most celebrated cemetery of Paris, named after the father confessor of Louis XIV, Père-Lachaise, whose grounds these used to be.
Here you may be willing to pause for breath, for you have not only traversed twenty arrondissements but twenty centuries of the town’s growth. For while Roman Paris (Lutetia) occupied the Cité and the Left Bank, close to the Seine, medieval Paris embraced little more than the first six arrondissements. The rest has been absorbed little by little, one or two villages becoming an arrondissement.