Chicago is the birthplace of the skyscraper. The Home Insurance Building, completed in 1885, is regarded as the world's first skyscraper. This building used the steel-frame method, innovated in Chicago. It was originally built with 10 stories, an enormous height in the 1800s, to a height of . It was later expanded to 12 stories with a height of . The building was demolished in 1931. New York City then began building skyscrapers as Chicago had done, and the two cities were virtually the only cities in the world with huge skylines for many decades. Chicago has always played a prominent role in the development of skyscrapers and three past buildings have been the tallest building in the United States. Being the inventor of the skyscraper, Chicago went through a very early high-rise construction boom that lasted from the early 1920s to the late 1930s, during which 9 of the city's 100 tallest buildings were constructed. The city then went through an even larger building boom that has lasted from the early 1960s. The tallest buildings are concentrated in various downtown districts such as the Loop, Streeterville, River North, the South Loop, and the West Loop. Other high-rises extend north along the waterfront into North Side districts such as the Gold Coast, Lincoln Park, Lakeview, Uptown and Edgewater. Some high-rises also extend south from downtown along the waterfront to South Side districts such as Kenwood, Hyde Park, and South Shore.