Please answer the following question: Given the following passage  "Louis-Philippe was overthrown by a popular uprising in the streets of Paris in 1848. His successor, Napoleon III, and the newly appointed prefect of the Seine, Georges-Eugène Haussmann, launched a gigantic public works project to build wide new boulevards, a new opera house, a central market, new aqueducts, sewers, and parks, including the Bois de Boulogne and Bois de Vincennes. In 1860, Napoleon III also annexed the surrounding towns and created eight new arrondissements, expanding Paris to its current limits.",  answer the following question. Note that the answer is present within the text.  Question: What successor improvement contributed to sanitation?
Answer:
sewers