A skyscraper is a very tall building or otherwise permanently habitable structure, typically defined as reaching a minimum height of either 100 metres (328 ft) or 150 metres (492 ft) in height; however, there remains no universally accepted definition of a skyscraper, other than being a high-rise. Skyscrapers can host a variety of spaces, typically including office, commercial, hotel, and residential space. Skyscrapers are a common feature in the downtown or central business districts (CBD) of major cities, especially in the Americas, Asia, and Australia, often due to a high demand for space and limited availability of land.