A ceremony took place at Ground Zero in New York today to mark the end of the operation to clean up the wreckage of the World Trade Centre in Lower Manhattan.
The clean-up operation has ended three months ahead of schedule at a cost of around $750 million. The operation received generous federal aid and is considered to have been unusually well-organised.
Almost 3,000 people were killed in the terrorist attacks. According to official records, only 1,092 remains have been formally identified.
