The last of the world’s super-towers?

Spare a thought for Blanchard, North Dakota. Until recently it was the proud home of the tallest structure in the world, the KVLY/KTHI, 629-metre TV mast, built in 1963. Now that record belongs to the Burj Dubai, which currently stands at about 725 metres and is still rising to its final height of more than 800 metres, the precise figure being secret. It's possible its height will never be officially revealed. Its developer EMAAR, behind which stands His Highness Sheikh Mohammed bin Rashid al Maktoum, ruler of Dubai, likes to keep the competition guessing.

There's unlikely to be much competition in the near future, except from other arms of Sheikh Mohammed's property empire. As well as beating Blanchard to the title of tallest manmade structure, the Burj Dubai will be the tallest inhabited building in the world, the record for which has inched upwards since the Empire State Building set it in 1931 at 381 metres. The Burj Dubai will have to be completed to qualify for this record, at which point it will wallop it.

The Empire State's record lasted until the Twin Towers of the World Trade Center broke it in 1972, soon surpassed by the Sears Tower in Chicago, until the Petronas Towers in Kuala Lumpur fudged their way past in 1998 by adding functionless spikes to their tops. Since 2004 the tallest inhabited building has been the little-celebrated Taipei 101 at 509 metres. Taipei 101 is like one of the less exciting Wimbledon winners - more Michael Stich than Björn Borg - and is best known for the rumour that the pressure it put on the earth was causing earthquakes.

In the 73 years from the Empire State to Taipei 101, the record for tallest building increased by a little more than a quarter. When the owners of the Burj Dubai's Armani apartments and its "boutique offices" move in next autumn, it will have raised the record by another 60 per cent. It will restore glamour to a title that had become a little boring. By being both the tallest structure and the tallest inhabited building it will remove the irritating niggle that comes from having different definitions. Whichever way you look at it, it will be higher than everything else.

The Burj is designed by the giant American practice SOM, which was also responsible for the Sears. It is already performing its primary purpose, which is raising higher the profile of that city between desert and sea with a genius for manufacturing its own mythology of construction. First came its seven-star hotel, followed by the artificial island shaped like a palm tree, followed by the archipelago (still under construction) shaped like a map of the world.

But the shape of the Palm cannot actually be seen except from a helicopter or Google Earth. At ground level it offers only a view of roads and the backs of luxury housing and even from flights into the city it is usually obscured by dust in the air. The Palm's new £1billion Atlantis Hotel suffered the rare ignominy of being accused by The Sun of bad taste ("the eighth chunder of the world"). The Burj Dubai, by contrast, presents a vertical shiver of silver to the starboard of incoming planes and keeps popping up in views from highways and souks and across parking lots, across the sandy plains of Dubai's landward side, and from the windows of hotels and offices in lesser towers.

It is ever-present and undeniably elegant, a slender shaft spiralling up from its broad base like a supermodel version of Brueghel's Tower of Babel. It adds distinction to the mob of towers, some of them blisteringly ugly, along the city's main artery, the 12-lane Sheikh Zayed Road. The city's gift shops are selling glass paperweights in the form of the tower, with a metal stalk on top to denote its unfinished status.

A vast 66million sq ft development called Downtown Burj Dubai spreads at its feet, including the just-opened largest shopping mall in the world, a cluster of residential towers, and the brand new Old Town, a turreted development clad in faux mud that is designed to look something like a historic Arab city. The most expensive fountain in the world, at $200million, is under construction. Apparently flats in the development facing the Burj command the highest rents, and the tower performs perfectly as an advertisement for the whole development. Mall, tower, fountain and Old Town are all doing different versions of the same job: promiscuously pushing marketing buttons intended to incite desire.

"The earth has a new centre," pronounces the PR gush and it is the power of image more than technology or practical need that has driven the tower upward. The tower's engineer, Bill Baker of the American architectural practice SOM, says he was "reasonably content to be just a little higher than somebody else" and that SOM's design was initially only slightly above Taipei 101 but that pressure came from his client to grow. Wind-testing models of the building showed how they could do this, and they kept adding height to the design even after foundations were going in.

"Why do people buy a Ferrari?" asks Baker. "It's not for transportation: you can get there in a Ford." The tower's height, together with its gilded lobbies, and high-level swimming pools which extend from inside to outside, created intense demand for its apartments and for the little offices that occupy its highest floors. According to Baker, floors 19-108 sold out in two nights at special, invitation-only sales events. The offices will serve "individuals who just need some space for themselves and a few retainers" and have a great desire to impress others.

Of course, the Burj faced technical challenges. Swaying is the main problem in buildings this high, and in storms the Burj will move at its top by one metre. One of the reasons the offices are at the top is that office workers are "the most tolerant user group" when it comes to sway - more tolerant, at least, than residents of Armani apartments. Nasty things called "vortex shadows", which are caused by wind and increase oscillation, had to be designed out. Unlike the Empire State and the Sears Towers, which are constrained by American city blocks, the Burj rises from a huge site, allowing it to stabilise itself by spreading its base.

Any lift that ran the full height would need a cable so heavy it would be unable to support its own weight, so journeys to the top will require a change at the 124th floor. The fact that the atmosphere is significantly cooler at the top than at the bottom creates strange currents of air that have to be dealt with. At the top the steel and glass cladding will be cleaned of desert sand every three weeks, by lucky men in specially designed cradles.

Like other skyscrapers, the Burj Dubai comes at the end of a boom. The Empire State marked the beginning of the Great Depression, the Sears the Seventies oil shock, the Petronas Towers the Nineties plummeting of Asian economies. This year the Dubai markets have lost 67 per cent of their value and last week EMAAR's shares dropped to their lowest level in four years.

This hasn't stopped Dubai recently announcing plans for another tower over a kilometre high and the vast Jumeirah Gardens development, which includes a three-pronged golden construction of even greater height. The latter is designed by Adrian Smith, who as architectural design director of SOM led a team on the Burj Dubai before leaving to set up his own business.

In theory the colossal wealth of Sheikh Mohammed, combined with the lowering of construction prices, means that these projects can go ahead regardless. Bill Baker says he expects his record to last five years, which would mean someone else starting something bigger now. But no one should be too surprised if the Burj Dubai continues to be the world's tallest building for a little longer.