The $787 million expansion of Philadelphia's Pennsylvania Convention Center was unveiled Friday morning. The convention center, which has grown by 62 percent, now has 1 million square feet of usable space. The venue offers 528,000 square feet of contiguous exhibit space, a new 55,400-square-foot ballroom and a total of 79 meeting rooms. The building welcomes two conventions today [wed] -- the Philadelphia International Flower Show and the National Association of Student Personnel Administrators, an arrangement that wasn't possible before the expansion. The 14,000-attendee Association of periOperative Registered Nurses convention will make use of the complete space beginning March 18. The Pennsylvania Convention Center Authority estimates the building's expansion will create 2,000 hospitality-industry jobs in the city, generate $10 million in income-tax revenue and contribute $150 million annually to the regional economy.