Alley may be paved, or unpaved, and a blind alley is a cul-de-sac. Modern urban developments may also provide a service road to allow for waste collection, or rear access for fire engines and parking. Because of geography, steps (stairs) are the predominant form of alley in hilly cities and towns. This includes Quebec City in Canada and in the United States Pittsburgh (see Steps of Pittsburgh), Cincinnati (see Steps of Cincinnati), Minneapolis, Seattle, and San Francisco as well as Hong Kong, Genoa and Rome. Some alleys are roofed because they are within buildings, such as the traboules of Lyon, or
Alley are footpaths and others narrow, sometimes cobbled, lanes open to traffic. Many of the alleys in the Back Bay and South End area are numbered (e.g. "Public Alley 438"). In the French Quarter of Charleston’s historic district, Philadelphia Alley (c. 1766), originally named "Cow Alley", is one of several picturesque alleys. In 1810 William Johnson gave it the name of "Philadelphia Alley", although locals call the "elegantly landscaped thoroughfare" "Dueler’s Alley". Starting on East Bay Street, Stolls Alley is just seventeen bricks wide at its start, and named for Justinus Stoll, an 18th-century blacksmith. For three hundred years, another of