There was a small tree at one end of the beam, which had been signed by workers and those gathered for the ceremony, and an American flag at the other.
Between them was a statue of William Penn, the city's founder. There is a myth that Philadelphia's sports teams will not win a championship as long as a building "rises above Billy Penn" on City Hall, said Bill Hankowsky, chief executive officer of Liberty Property Trust, the Malvern company that is building Comcast Center.
He was referring to the controversy two decades ago when One Liberty Place, also built by Liberty, became the first to break that barrier.
"We don't believe in the myth, but to be safe we've added the statue of Billy Penn," Hankowsky said.