The Burj Khalifa is a megatall skyscraper in Dubai, United Arab Emirates. It is the tallest structure in the world, standing at 829.8 m (2,722 ft).

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 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 of Burj Khalifa is derived from patterning systems embodied in Islamic architecture, incorporating cultural and historical elements particular to the region, such as in the Great Mosque of Samarra. The Y-shaped plan is designed for residential and hotel usage.

A buttressed core structural system is used to support the height of the building, and the cladding system is designed to withstand Dubai’s 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 workers from South East Asia, who were allegedly treated poorly.