On Sunday, the city of Paris looked entirely different. Instead of being clogged with cars as Paris usually is, the city streets were filled with pedestrians, bikers, and the occasional roller skater. Paris successfully held a Car Free Day in 2015 and 2016, but this was the first time the city council extended the boundaries to include the entire city. While the event allowed the citizens of Paris to imagine a city without cars, the experience also brought concrete results. Researchers reported that nitrogen dioxide levels were down significantly near major roads while noise pollution decreased 20 percent compared to a regular Sunday in Paris.