The 101-story structure looks like a stack of gift boxes, but developers liken it to a bamboo shoot with notched sections. Called Taipei 101, the building will house offices, a mall and an observatory.
Wearing a white hard hat, Taipei Mayor Ma Ying-jeou and a small group of engineers, developers and officials watched the 198-foot pinnacle being installed from an observation deck on the 91st floor.
"This ceremony marks a historical moment that Taipei 101 is officially declared the tallest building in the world," Ma said.
It tops the previous titleholder, the Petronas Towers in Kuala Lumpur, Malaysia, which measures 1,483 feet. Chicago's Sears Tower, at 110 stories and 1,450 feet, is the tallest building in North America.
The structure — which opens officially next year — will have the world's fastest elevators and a stairway that leads to the top spire at 1,676 feet, developers have said.
Some worry the building would be dangerous in earthquake-prone Taiwan. But the skyscraper's developers have said that the closest fault line is 660 feet from the building, and the fault hasn't been active in 45,000 years.
Harace Lin, president of the Taipei Financial Center Corp., which is responsible for the building's construction and operation, assured tenants Friday the building would be safe.
Taipei 101 is not expected to hold the tallest-building title for long. In China, developers say the Shanghai World Financial Center will be higher when it's completed in 2007.
By William Foreman