As the US marks the 12th anniversary of the 9/11 attacks, the building which replaced the two towers of the World Trade Center is nearing completion.

This time-lapse video shows the nine years of construction on the new tower, known as One World Trade Center, from foundation to the newly placed spire.

The building is now the tallest in the Western hemisphere with the addition of the spire, topping out at a symbolic 1,776 ft (541m).

Time-lapse courtesy of EarthCam