Engineers assessing the damage caused by the collapse of the World Trade Centre in New York say that 111 buildings within a four-block radius of the twin towers could collapse or need to be pulled down.
Engineers say the collapse, which sent 78,000 tonnes of steel and concrete crashing, caused a shockwave similar to that of an earthquake. The 111 buildings, which have been evacuated, are being surveyed.
The 54-storey American Express building at 1 Liberty Plaza is already leaning dangerously and may need to be pulled down if it does not collapse.
