The center, built in 1993, is currently at 640,000 sf. Construction of the expansion will generate at least $10 million a year in state income tax, says Michael J. Masch, state secretary of the budget and board member of the Convention Center Authority. Once completed in 2010, Masch expects it to generate almost $1.1 billion per year in spending.

"Supporting this expansion is vital to our goal of improving the state's economy by investing in jobs and stimulating travel to the commonwealth," says Gov. Ed Rendell.Some 40% of the total hotel room nights used each year in the city come from conventions--the national average is just 27%. That works out to an extra 280,000 room nights per year and an extra $140 million in regional economic activity.

"The convention center has been a huge hospitality engine for Philadelphia from the time it opened in 1993," says Philadelphia Mayor John Street. "Its expansion will only enhance that momentum and help us move full speed ahead as a premier tourism destination."