Paris is often referred to as the 'City of Light' (''La Ville Lumière''), both because of its leading role during the Age of Enlightenment and more literally because Paris was one of the first large European cities to use gas street lighting on a grand scale on its boulevards and monuments. Gas lights were installed on the Place du Carrousel, Rue de Rivoli and Place Vendome in 1829. By 1857, the Grand boulevards were lit. By the 1860s, the boulevards and streets of Paris were illuminated by 56,000 gas lamps. Since the late 19th century, Paris has also been known as ''Panam(e)'' () in French slang.