Architect David Childs speaks next to a model of the redesigned Freedom Tower
New York officials have unveiled a new design for the Freedom Tower that will be the centerpiece of the redeveloped World Trade Center site.   Security concerns led to the redesigned tower, which will be the tallest building in the United States when completed. 

Officials say the new design will make the Freedom Tower the safest skyscraper in the world. The original design, by architect Daniel Liebeskind, was chosen after an international competition that attracted top architects and designers from across the globe. But concerns expressed by the police department about the building's safety sent the designers back to the drawing board. 

Police were particularly worried that the building was too close to a major highway and would be vulnerable to truck bombs. The redesigned tower will be set farther away from the thoroughfare. The base will be reinforced with more than 5,000 kilograms of concrete and 100,000 tons of steel beams.

New York Mayor Michael Bloomberg says the new design shows the city is putting safety first as it responds to the many challenges involved in redeveloping the site.

"Construction will climax the greatest comeback in the history of our city and for generations to come it will be a powerful beacon of freedom to people around the world," said Mr. Bloomberg.  "The designers of the Freedom Tower have also paid great attention to providing a safe and secure environment for everyone who will work in it and visit it."

The redesigned tower will be the same height as the destroyed World Trade Center towers, 396 meters. But an additional 122 meter spire will bring its total height to 541 meters, or 1,776 feet, a symbol of the year 1776 when the United States declared its independence from Great Britain.  Shimmering blast resistant panels will cover concrete walls and will reflect light.

Numerous bureaucratic delays have hampered the site's development. Officials now say the building will be ready for tenants by 2010.