Two window cleaners who were stranded 69 storeys above street level when their cradle partially collapsed have been rescued.
Firefighters cut panes of glass to rescue the pair from the south side of the newly-opened 1 World Trade Centre in New York.
The city's fire department said the men were tethered and communicating with rescuers during their ordeal.
Joe Pentangelo, spokesman for the Port Authority of New York and New Jersey, which owns the building, said it appeared that a cable on the cradle had broken.
Police official John Miller said the cradle was hanging at "a 75-degree angle".
The cable apparently snapped at around 1pm local time and the workmen were pulled inside the building at around 2.15pm.
The washers were stuck for nearly two hours before their dramatic rescue, as New Yorkers looked on from the ground and people around the country watched on live TV.
The scaffold accident, which officials said was caused by a malfunctioning cable, happened little more than a week after workers began moving into the nation's tallest building.
It was unclear whether the scaffold had been used on the 1,776ft, 104-storey skyscraper before or whether anything about the building's design complicates working a scaffold. Officials stressed that firefighters had trained for various emergencies at the tower, the centrepiece of the rebuilt World Trade Centre.
The window washers' ordeal began on the lower Manhattan building's south side when one of the platform's four cables abruptly developed slack, Fire Commissioner Daniel Nigro said. The open-topped platform tilted sharply and swayed slightly in the wind between the 68th and 69th floors, he said.
"It suddenly went from horizontal to nearly vertical," he said.
Officials have not determined what caused the cable problem. The cables are controlled from the scaffold vehicle, the fire commissioner said.
About 100 firefighters rushed to the skyscraper, some of them lowering ropes from the roof so the workers could secure themselves and a two-way radio for them to communicate, Mr Nigro said. The workers were harnessed to the platform.
Firefighters first used diamond cutters to saw through part of a two-layered glass window on the 68th floor. They shattered the thick glass in place, then carefully pulled the broken pieces into the building.
They also began inching another scaffold down the building as a back-up rescue plan, but they were able to bring the workers to safety through the 4ft by 8ft window hole.
The workers had mild hypothermia but seemed otherwise okay, Mr Nigro said. They were taken to a hospital to be checked out.
The silvery skyscraper, which rose from the ashes of the September 11 2001 terror attack, reopened last week to 175 employees of magazine publisher Conde Nast. About 3,000 more Conde Nast employees are expected to move in by early next year, eventually occupying 25 floors of the tower.