The Burj Khalifa, as it is now known, rises 828 metres into the sky and is the tallest building in the world. But this begs the question: How did Emaar and its architects arrive at that height? Was it the limit of economic sustainability for a tall building? Was it randomly chosen by darts?

Neither is the answer, as Crane Country has discovered. In fact, the height is derived from Emaar CEO Mohamed Alabbar's deep interest in feng shui and numerology. From the beginning of the design process, Mr Alabbar insisted on the incorporation of the number 8, according to Adrian Smith, the designer of the Burj Khalifa.

"[Mr Alabbar] believes in feng shui to some degree," Mr Smith said in an interview this morning (more on that later). "He brought in a feng shui expert to look at the tower when it was being designed. It's also a lucky number in Chinese culture. It brings good fortune. So at one point we were shooting for 808 metres, then 818, then finally 828."

The number 8 also has some significance in Islam, according to a cursory search on the internet.

A former executive at Emaar said that Mr Alabbar also insisted on using 888 as a price point. So, many apartments would have prices like Dh7,917,888. There is a discussion of this price phenomenon on the Skyscraper City forum.

Other "coincidences?"

• World's highest mosque (located on the 158th floor)
• Residential apartments sold out within "8 hours"
• Eight escalators in the building
• Outdoor observation deck is at 440 metres (4+4=8!)
• Inauguration was on Jan 4, 2010 (01042010) --> (1+4+2+1=8!) at 8 p.m. --- Hat tip to @gerald_d and @esperanca 
• If you add up the letters of "Burj Dubai" - the original name - you get 88. --- Hat tip to Andrew Henderson
  

Obviously, you can find whatever number you want if you look hard enough. Still, an interesting tidbit about Dubai's newest global celebrity building.