Exactly thirteen years ago on Thursday, one of the most recognisable skylines on the planet was left scarred by attacks that would dramatically change the course of world events.
Along with attacks on the Pentagon and the downing of a fourth airliner in Pennsylvania, 2,977 civilians were killed.
As a tribute - and a sign of defiance - authorities decided to build an even taller tower at the site of what was dubbed Ground Zero.
One World Trade Center is 1,776 ft high, a reference to the year of the US declaration of independence.
These slider photos show the remarkable contrast between the destruction wrought on that day and what has been built since in tribute.
Slide the arrow tool left and right to compare photos...