Although I enjoy walking around, to and from school, when the distance is longer or the weather is bad, I always use the metro.
In Paris, the city leaders are trying to reduce the use of cars in the city in order to help the environment. For example, my street (Champs-Elysees) has a special "Pedestrian Day" one time per month where the street is closed to cars, and people can walk across the street freely. The large metro system in Paris also helps combat air pollution by reducing the number of cars in the city.
