One of the largest cathedrals (some 135m/443 ft. long) built in Europe during the 19th century, this massive structure has almost swallowed its 12th-century predecessor, built on the ruins of a temple of Diana. Its striped exterior is a bastardized Romanesque-Byzantine style with domes and cupolas; the intricate interiors include mosaic floors and red-and-white marble banners. The cathedral’s architecture is particularly arresting now that it overlooks Marseille’s redeveloped port and dockland areas. It also provides shady respite from sightseeing on a summer’s day.