The Burj Khalifa is a tall building with multiple floors.
A skyscraper is a tall , continuously habitable building having multiple floors .. floors. Storey. When the term was originally used in the 1880s it described a building of 10 to 20 floors but now describes one of at least 40 -- 50 floors .. floors. Storey. Mostly designed for office , commercial and residential uses , a skyscraper can also be called a high-rise , but the term `` skyscraper '' is often used for buildings higher than 50 m. For buildings above a height of 300 m , the term `` supertall '' can be used , while skyscrapers reaching beyond 600 m are classified as `` megatall '' .. high-rise. Tower block. One common feature of skyscrapers is having a steel framework that supports curtain walls .. curtain walls. curtain wall ( architecture ). 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 .. curtain walls. curtain wall ( architecture ). Some early skyscrapers have a steel frame that enables the construction of load-bearing walls taller than of those made of reinforced concrete .. steel frame. steel frame. reinforced concrete. reinforced concrete. Modern skyscrapers ' walls are not load-bearing , and most skyscrapers are characterized by large surface areas of windows made possible by steel frames and curtain walls .. curtain walls. curtain wall ( architecture ). However , skyscrapers can have curtain walls that mimic conventional walls with a small surface area of windows .. curtain walls. curtain wall ( architecture ). Modern skyscrapers often have a tubular structure , and are designed to act like a hollow cylinder to resist wind , seismic , and other lateral loads .. tubular structure. Tube ( structure ). cylinder. cylinder. To appear more slender , allow less wind exposure , and transmit more daylight to the ground , many skyscrapers have a design with setbacks , which are sometimes also structurally required .. setbacks. Setback ( architecture )