Query: The Burj Khalifa is a tall building with multiple floors.

Relevant passages:
Skyscraper <=SEP=> A skyscraper is a tall , continuously habitable building having multiple floors . 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 . 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 '' .   One common feature of skyscrapers is having a steel framework 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 of those made of 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 . 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 are sometimes also structurally required .

Burj Khalifa <=SEP=> The Burj Khalifa ( برج خليفة , Arabic for `` Khalifa Tower '' ; pronounced -LSB- langˈbɝdʒ_kə ` li : fə -RSB- ) , known as the Burj Dubai before its inauguration , is a megatall skyscraper in Dubai , United Arab Emirates . With a total height of 829.8 m including the antenna and a roof height of 828 m , the Burj Khalifa is currently the tallest structure in the world since topping out in late 2008 .   Construction of the Burj Khalifa began in 2004 , with the exterior completed 5 years later in 2009 . The primary structure is reinforced concrete . The building was opened in 2010 as part of a new development called Downtown Dubai . It is designed to be the centrepiece of large-scale , mixed-use development . The decision to construct the building is reportedly based on the government 's decision to diversify from an oil-based economy , and for Dubai to gain international recognition . The building was named in honour of the ruler of Abu Dhabi and president of the United Arab Emirates , Khalifa bin Zayed Al Nahyan ; Abu Dhabi and the UAE government lent Dubai money to pay its debts . The building broke numerous height records , including its designation as the tallest tower in the world .   Burj Khalifa was designed by Adrian Smith , then of Skidmore , Owings & Merrill ( SOM ) , whose firm designed the Willis Tower and One World Trade Center . Hyder Consulting was chosen to be the supervising engineer with NORR Group Consultants International Limited chosen to supervise the architecture of the project . The design is derived from the Islamic architecture of the region , such as in the Great Mosque of Samarra . The Y-shaped tripartite floor geometry is designed to optimize residential and hotel space . A buttressed central core and wings are used to support the height of the building . Although this design was derived from Tower Palace III , the Burj Khalifa 's central core houses all vertical transportation with the exception of egress stairs within each of the wings . The structure also features a cladding system which is designed to withstand Dubai 's hot summer temperatures . It contains a total of 57 elevators and 8 escalators .   Critical reception to Burj Khalifa has been generally positive , and the building has received many awards . However , the labour issues during construction were controversial , since the building was built primarily by migrant workers from South Asia with several allegations of mistreatment . Poor working conditions are common , as the result of the lack of minimum wage laws in the United Arab Emirates . Several instances of suicides have been reported , which is not uncommon for migrant construction workers in Dubai despite safety precautions in place .