A skyscraper is a tall continuously habitable building having multiple floors.Some early skyscrapers have a steel frame that enables the construction of load-bearing walls taller than of those made of reinforced concrete.Modern sources define skyscrapers as being at least 100 meters (330 ft)[1] or 150 meters (490 ft)[2] in height, though there is no universally accepted definition, other than being very tall high-rise buildings.This idea was invented by Viollet le Duc in his discourses on architecture.[3] 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.Skyscrapers may host offices, hotels, residential spaces, and retail spaces.