At 10.29 this morning, the exact time the second of the twin towers collapsed on September 11th, the last steel beam from the wreckage of the World Trade Centre will be removed. A fire department bell will ring out, and the long and distressing search for the remains of 2,823 victims will officially come to an end.
The 58-tonne beam was cut down on Tuesday evening in a moving ceremony accompanied by the wail of pipes and shouts of "USA!" from 250 rescue workers who have toiled for 260 days to remove the rubble and locate human remains. It will be driven out this morning on a flatbed truck draped in black and covered with the American flag.
The rusting 36-foot-high beam, labelled 1,001B, helped support a corner of the south tower. It had been plastered with photographs and spray-painted with tributes to rescue personnel - 37 Port Authority police, 23 New York police and 343 firemen - who died on September 11th .
Mr Dick Nolan, who helped build the towers 30 years ago, was at the controls of the crane that lifted the beam. "I didn't enjoy this," he said. "But I feel privileged to be lifting out the last piece of steel."
A platform for Mayor Michael Bloomberg and other dignitaries has been erected on the floor of the vast empty pit for today's solemn event, which will mark a profound shift - physical and psychological - from one of the world's biggest recovery operations to an equally daunting period of reconstruction.
An empty stretcher with a folded American flag representing the hundreds of victims whose remains have not been found will be carried up a steel exit ramp and taken in procession along West Street to Canal Street in lower Manhattan.
"The construction workers who have dedicated themselves to this effort are on the verge of completing an enormous job, and in many ways this is their night to reflect and remember," Mayor Bloomberg said, as he shook hands with the last workers leaving ground zero.
As the final pile of rubble was cleared on Tuesday, firefighters found five small bones, which will be taken for DNA testing. The remains of only 1,092 victims have been identified but almost 20,000 body parts have been recovered. The process of identification will continue for at least eight more months.
Many of the victims' relatives have objected to the ceremony occurring on a work day rather than at the weekend, when the mayor has established a practice of leaving the city for recreation.
A memorial over almost half of the 16-acre site will most likely be built, according to Mr Louis Tomson, head of the Lower Manhattan Development Corporation, which has received $2 billion in federal funds to redevelop the downtown district.