Tall Order: Super Skyscraper Plan

It will be more than 1km high, have 150 lifts and will take over 10 years to construct, say the developers of what could become the world's tallest building.

The Islamic design-inspired Nakheel Tower will be the centre piece of a multi-billion pound inner-city harbour development in Dubai.

Its makers claim it will be so tall that the tower will experience five different microclimatic conditions above its height.

And high speed shuttle lifts will mean people will be able to see the sunset twice - from the bottom and again from the top of the building.

Nakheel - the company that created man-made islands in the shapes of a palm tree and the world - is behind the build.

Its chief executive officer, Christopher O'Donnell, cautiously told a news conference: "From our perspective, we are building a tower that's going to be over 1km in height.

"This is a complete iconic development. It may be the tallest. Someone may build something taller."

But "tallest building" claims are notoriously difficult to make. Debates about what counts as a candidate include whether buildings under construction should be considered and whether roof-top antennas count.

What is certain is that the tower will climb above the current holder of the "world's tallest building" position - the Emirate's own Burj Dubai.

Asked if the firm was worried about embarking on such a development during a global financial crisis, Mr O'Donnell said: "It was always going to be a project that would take 10 years-plus.

"When you go about trying to fund a project like this, you have to take account of the economic cycles."

The company would not comment on how much the tower will cost to build.

Also:

Nakheel is to trump rival Emaar Properties in the contest to build the world's tallest building, with the Dubai-owned developer on Sunday unveiling plans for a tower that will dwarf the Burj Dubai.

Nakheel is poised to build a tower that will be more than one kilometre high, as part of a 140 billion-dirham ($38.12 billion) project that will include the world’s first inner city harbour, company executives said.

Emaar's Burj Dubai, currently the tallest man made structure in the world at over 630 metres, is expected to be up to 900 metres tall upon completion in early 2009. The company has refused to reveal its final height.