I worked in the building above the Holland tunnel... (1 Hudson Sq.)...and was 'corralled' on that block for several hours.. but, took 27 photos on my way to work that day, along Canal st., NYC..
For each anniversary, flood lights were placed at the site near the foot print of the towers. When you were close to base of the lights, you could see glowing particles drifting up to the sky. It was an amazing image.