I have just got back from NYC. We visited the 9/11 tribute center and took a tour of Ground Zero with two fire fighters who were there and survived 9/11. One fire fighter, Al, lost 15 men from his fire house alone. He is a piper and pipes in the fire service band. He went to every single funeral/memorial service after 9/11. Since that day he has piped at 81 further funerals of fire fighters that have died since as a result respiratory diseases and cancers caused by the dust cloud as the towers collapsed. Goodness knows how many other emergency workers/civilians have died since because of the dust cloud.It was so moving listening the Al and Steve's stories and I feel privileged to have paid my respects at the site.
Educational resources here: tributewtc.org/education
We also visited the pentagon in Washington DC. My children, 14 and 12, did not have a clue that a plane hit the pentagon on the same day. They knew about the twin towers and United 93, but not the pentagon.
The pentagon is the biggest office building in the world although it is only 4 storeys high. It is made up of five pentagonal office blocks one inside another. 41,000 people work there each day! On 9/11 the side of the pentagon that was hit was being refurbished. It was having steel reinforcement beams etc fitted as anti terrorism protection. Usually 7,000 people would have been working in that part of the building. However, because of the building work, there was next to no one in that part of the building. 125 people were killed in the pentagon. The plane should have gone in one side and out the other, potentially killing 14,000!! But because of the reinforcement beams that had been fitted (and that the plane hit the top of the Sheraton hotel on the way in) it only went through A,B and C blocks on the one side...there by the grace of a God, and all that.
On the pentagon plane were 64 people. (The pentagon memorial is beautiful- google image it). There were 5 children on the plane, 2 in a family and 3 children without a family member. We only had a short amount of time in the pentagon memorial room in the rebuilt part of the building, but each person who died has a biography in a memorial book. We looked up 11 year old Bernard Brown's biography and found he was on plane with his teacher as he had won a science competition at school and national Geographic had organised a trip to California as a prize. Read his story here:
cynamans.hubpages.com/hub/911-An-Untold-Story-of-Heart-Break
Hope your assembly goes well and this info/resources help.