An important legacy of Napoleon III's reign was the rebuilding of Paris under the supervision of Georges-Eugène Haussmann. One purpose was reduce the ability of future revolutionaries to challenge the government by blocking the small, medieval streets of Paris with barricades. However, the main reason for the complete transformation of Paris was Napoleon III's desire to modernize Paris based on what he had seen of the modernizations of London during his exile there in the 1840s.