At 829.8 meters, the Burj Khalifa is tall enough that residents above the 150th floor break their Ramadan fast about three minutes after those at street level, because they can still see the sun. Dubai under Sheikh Mohammed bin Rashid Al Maktoum built it as a global billboard for diversifying away from oil, and a brief first inspired by Seoul’s Tower Palace 3 grew into the anchor of the two square kilometer Downtown Dubai. Ground broke in 2004, and the 2008 financial crisis hit a city carrying at least 80 billion dollars in debt. Abu Dhabi and the UAE federal government stepped in, and at the January 2010 opening the tower long marketed as Burj Dubai was renamed for Abu Dhabi’s ruler, Sheikh Khalifa bin Zayed Al Nahyan. Ten months later prices had fallen 40 percent, with 825 of 900 apartments empty.

Skidmore, Owings & Merrill and structural engineer Bill Baker used Fazlur Rahman Khan’s bundled tube idea in a Y-shaped plan inspired by the Hymenocallis flower, with 27 spiraling setbacks echoing the minaret at Samarra to break up vortex shedding. The top still sways about 1.5 meters. The foundation rests on 192 friction piles over 50 meters deep, protected from corrosive groundwater by a cathodic system, and concrete was poured only at night and mixed with ice to control curing heat. Behind the Armani hotel and the Atmosphere restaurant on floor 122 was a migrant workforce under the kafala system, which the BBC and Human Rights Watch documented with low wages and confiscated passports.

• How three wings brace one another against wind and twisting forces
• A new high pressure Putzmeister pump built to push concrete about 600 meters up
• More than 35,000 tons of steel salvaged from East Germany’s demolished Palace of the Republic
• 36 workers needing three to four months to clean more than 24,000 windows once, with ropes at the spire
• 244 meters of unoccupied vanity height that would rank as Europe’s 11th tallest skyscraper on its own