The National September 11 Memorial will be unveiled on the 10th anniversary of the attacks next month. Workers have been toiling at the site for seven years, but this time-lapse video crunches it all down to just a minute and a half.

Using footage from live webcam site EarthCam, the past several years of construction make for some pretty cool before-and-after imagery.

Take a look at the video below:

[via The Daily What]