the US Department of Labor of a special report on housing conditions and solutions elsewhere in the world, The Housing of Working People, it ultimately led to the passage of the Tenement House Act of 1901, known as the New Law, which implemented the Tenement House Committee's recommendation of a maximum of 70 percent lot coverage and mandated strict enforcement, specified a minimum of 12 feet for a rear yard and 6 feet for an air and light shaft at the lot line or 12 feet in the middle of the building (all of these being increased for taller buildings), and required running water and water closets in every apartment and a window in every room. There were also fire-safety requirements. These rules are still the basis of New York City law on low-rise buildings, and they have made single-lot development uneconomical. Most of the purpose-built tenements in New York were not slums, although they were not pleasant to be inside, especially in hot weather, so people congregated outside, made heavy use of the fire escapes, and slept in summer on fire escapes, roofs, and sidewalks. The Lower East Side Tenement Museum, a five-story brick former tenement building in Manhattan that is a National Historic Site, is a museum devoted to tenements in the Lower East Side. Other famous tenements in the US include tenement housing in Chicago, in which various housing areas were built to the same affect as tenements in New York. Edinburgh and Glasgow Tenements make up a large percentage of the housing stock of Edinburgh and Glasgow in Scotland. Glasgow tenements were built to provide high-density housing for the large number of people immigrating to the city in the 19th and early 20th century as a result of the Industrial Revolution, when the city's population boomed to more than 1 million people. Edinburgh's tenements are much older, dating from the 17th century onwards, and some were up to 15 storeys high when first built, which made them among the tallest houses in the world at that time. Glasgow tenements were generally built no taller than the width of the street on which they were located; therefore, most are about 3–5 storeys high. Virtually all Glasgow tenements were constructed using red or blonde sandstone, which has become distinctive. In Edinburgh, residential dwellings in the UNESCO World Heritage Sites of the medieval Old Town and Georgian New Town