Skyscraper

A skyscraper is a tall building with many habitable floors. Most modern sources define skyscrapers as being at least 100 metres (328 ft) or 150 metres (492 ft) in height, though there is no universally accepted definition, other than being very tall high-rise buildings. Skyscrapers may host offices, hotels, residential spaces, and retail spaces. Skyscrapers are a common feature of large cities, especially in the Americas, Asia, and Australia, often due to a high demand for space and limited availability of land. One common feature of skyscrapers is having a steel frame that supports curtain walls. These curtain walls either bear on the framework below or are suspended from the framework above, rather than resting on load-bearing walls of conventional construction. Some early skyscrapers have a steel frame that enables the construction of load-bearing walls taller than those made of reinforced concrete. Modern skyscraper walls are not load-bearing, and most skyscrapers are characterized by large surface areas of windows made possible by steel frames and curtain walls. However, skyscrapers can have curtain walls that mimic conventional walls with a small surface area of windows. Modern skyscrapers often have a tubular structure, and are designed to act like a hollow cylinder to resist wind, seismic, and other lateral loads. To appear more slender, allow less wind exposure and transmit more daylight to the ground, many skyscrapers have a design with setbacks, which in some cases is also structurally required. Skyscrapers first appeared in the United States at the end of the 19th century, especially in the cities of Chicago and New York City. Following a building boom across the western world in the early 20th century, skyscraper development was halted in the 1930s by the Great Depression, and did not resume until the 1950s. A skyscraper boom in the downtowns of many American cities took place during the 1960s to 1980s. Towards the second half of the 20th century, skyscrapers began to be built more frequently outside the United States, particularly in East Asia and Southeast Asia during the 1990s. China has since overtaken the United States as the country with the most skyscrapers. Skyscrapers are an increasingly global phenomenon, and can be found in at least 70 countries. There are over seven thousand skyscrapers over 150 m (492 ft) in height worldwide, most of which were built in the 21st century. Over three-quarters of skyscrapers taller than 150 m are located in Asia. Twenty cities in the world have at least a hundred skyscrapers that are taller than 150 m (492 ft), most recently Singapore, Hangzhou, Moscow, and Toronto in 2025. The city with the most skyscrapers in the world is Hong Kong, with 569 skyscrapers, followed by Shenzhen in China with 465, New York City with 324, and Dubai in the United Arab Emirates with 269. The tallest skyscraper in the world is the Burj Khalifa in Dubai, with a height of 828 m (2,717 ft).