Please answer the following question: Extract the answer to the question from the following context. Question: What successor improvement contributed to sanitation? Context: 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:
sewers