This did not solve the problem of the slums around Notre Dame and the Quartier Latin, however. Improvements in this area took another few years and the intervention of Napoleon III who was worried about how to patrol the streets to keep them safe. He asked Baron Haussmann to come up with a solution, who proceeded to knock down the slums and replace them with wide boulevards that whole armies could (and do) march down. Haussmann changed the face of Paris forever, building acres of mansion blocks on large avenues, above which tower the presidential monuments. Today, if you have enough money, you can still live in the apartments in the shadow of the classical Louvre, Panthéon and Arc de Triomphe; industrial Eiffel Tower and Centre Pompidou; golden Invalides; and the modern glass Pyramide du Louvre.