DUBAI (AP).- Dubai opened the world's tallest building amid tight security on Monday, celebrating the tower as a bold feat on the world stage despite the city state's shaky financial footing.

But the final height of the Burj Dubai — Arabic for Dubai Tower — remained a closely guarded secret on the eve of its opening. At more than 2,625 feet (800 meters), it long ago vanquished its nearest rival, the Taipei 101 in Taiwan.

The Burj's record-seeking developers didn't stop there.

The building boasts the most stories and highest occupied floor of any building in the world, and ranks as the world's tallest structure, beating out a television mast in North Dakota. Its observation deck — on floor 124 — also sets a record.

"We weren't sure how high we could go," said Bill Baker, the building's structural engineer, who is in Dubai for the inauguration. "It was kind of an exploration. ... A learning experience"

Baker, of Chicago-based architecture and engineering firm Skidmore, Owings & Merrill, said early designs for the Burj had it edging out the world's previous record-holder, the Taipei 101, by about 33 feet (10 meters). The Taiwan tower rises 1,667 feet (508 meters).

The Burj's developer, Emaar Properties, kept pushing the design higher even after construction began, eventually putting it about 984 feet (300 meters) taller than its nearest competitor, Baker said. He is keeping quiet about the exact height.

Dubai's ruler will open the tapering metal-and-glass spire with a fireworks display Monday evening.

Security is expected to be tight. Local newspapers quoted Maj. Gen. Mohammed Eid al-Mansouri, head of the protective security and emergency unit for Dubai Police, saying more than 1,000 security personnel, including plainclothes police and sharpshooters, will be deployed to secure the site for the opening.

Work on the Burj Dubai began in 2004 and continued rapidly. At times, new floors were being added almost every three days, reflecting Dubai's raging push to reshape itself over a few years from a small-time desert outpost into a cosmopolitan urban giant packed with skyscrapers.

By January 2007, thousands of laborers, many of them brought in on temporary contracts from India, had completed 100 stories.

The finished product contains more than 160 floors. That is over 50 stories more than Chicago's Willis Tower, the tallest record-holder in the U.S. formerly known as the Sears Tower.

At their peak, some apartments in the Burj were selling for more than $1,900 per square foot, though they now can go for less than half that, said Heather Wipperman Amiji, chief executive of Dubai real estate consultancy Investment Boutique.

Besides luxury apartments and offices, the Burj will be home to a hotel designed by Giorgio Armani.

It's also the centerpiece of a 500-acre development that officials hope will become a new central residential and commercial district in this sprawling and often disconnected city. It is flanked by dozens of smaller but brand-new skyscrapers and the Middle East's largest shopping mall.

That layout — as the core of a lower-rise skyline — lets the Burj stand out prominently against the horizon. It is visible across dozens of miles of rolling sand dunes outside Dubai. From the air, the spire appears as an almost solitary, slender needle reaching high into the sky.

The Burj's opening comes at a tough time for Dubai's economy. Property prices in newer parts of the sheikdom have collapsed by nearly half over the past year.

The city-state turned to its richer neighbor Abu Dhabi for a series of bailouts totaling $25 billion in 2009 to help cover debts amassed by a network of state-linked companies. Burj developer Emaar is itself partly owned by the government, but is not among the companies known to have received emergency cash.

Emaar has said the entire Downtown Burj Dubai development, which includes the tower, will cost $20 billion to build. Sales of properties around the Burj are meant to help pay for the tower itself, which analysts say is unlikely to be profitable on its own.

Jan Klerks, research and communications manager for the Council on Tall Buildings and Urban Habitat, which tracks world's tallest claims, said the building's real value might be that it is the "biggest city marketing campaign" Dubai could have come up with.

"Put your name and that of the Burj Dubai on an envelope, and no postal service in the world will have problems delivering the mail," he said.

Copyright 2010 The Associated Press.