within the building. If utilizing the stack effect, buildings must take extra care to design for fire separation techniques, as the stack effect can also exacerbate the severity of a fire. Skyscrapers are considered to be internally dominated buildings because of their size as well as the fact that a majority are used as some sort of office building with high cooling loads. Due to the microclimate created at the upper floors with the increased wind speed and the decreased dry bulb temperatures, the cooling load will naturally be reduced because of infiltration through the thermal envelope. By taking advantage of the naturally cooler temperatures at higher altitudes, skyscrapers can reduce their cooling loads passively. On the other side of this argument, is the lack of shading at higher altitudes by other buildings, so the solar heat gain will be larger for higher floors than for floors at the lower end of the building. Special measures should be taken to shade upper floors from sunlight during the overheated period to ensure thermal comfort without increasing the cooling load. History of the tallest skyscrapers At the beginning of the 20th century, New York City was a center for the Beaux-Arts architectural movement, attracting the talents of such great architects as Stanford White and Carrere and Hastings. As better construction and engineering technology became available as the century progressed, New York City and Chicago became the focal point of the competition for the tallest building in the world. Each city's striking skyline has been composed of numerous and varied skyscrapers, many of which are icons of 20th-century architecture: The E. V. Haughwout Building in Manhattan was the first building to successfully install a passenger elevator, doing so on 23 March 1857. The Equitable Life Building in Manhattan was the first office building to feature passenger elevators. The Home Insurance Building in Chicago, which was built in 1884, was the first tall building with a steel skeleton. The Singer Building, an expansion to an existing structure in Lower Manhattan was the world's tallest building when completed in 1908. Designed by Ernest Flagg, it was tall. The Metropolitan Life Insurance Company Tower, across Madison Square Park from the Flatiron Building, was the world's tallest building when completed in 1909. It was designed by the architectural firm of Napoleon LeBrun & Sons and stood tall. The Woolworth Building, a neo-Gothic "Cathedral of Commerce" overlooking New