The Burj Khalifa , known as the Burj Dubai before its inauguration, is a megatall skyscraper in Dubai, United Arab Emirates. It has a roof height of 828‚ m (2,717‚ ft), and with its antennaincluded, it stands a total height of 829.8‚ m (2,722‚ ft), making it the tallest building and the tallest structure in the world.

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 build 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 ofAbu 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 theGreat 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.