Follow the men and women who manage the Paris sewers every day in a dark, confined setting fraught with lethal gas to see how this parallel network operates. This gigantic, complex network carries away Parisians' wastewater and provides them with clean drinking water. Built in the 19th century, how do these sewers improve the health of the environment?

Follow the men and women who manage the Paris sewers every day in a dark, confined setting fraught with lethal gas to see how this parallel network operates. This gigantic, complex network carries away Parisians' wastewater and provides them with clean drinking water. Built in the 19th century, how do these sewers improve the health of the environment?