9/11 anniversary: how the World Trade Center site was rebuilt

Next Saturday marks 20 years since the world was traumatised by the 9/11 terrorist attack on the World Trade Center. In the first piece of our series marking the anniversary of the attack, we look at how the site was rebuilt.
Once the tallest buildings in the world, the 110-storey World Trade Center towers in lower Manhattan, New York, were destroyed on 11 September 2001 in a terrorist attack.
The attack shocked the world, causing a global recession, leading to the US invasion of Afghanistan and