if he is so sure that its concrete, why hasn't he contacted those who built the towers? The businesses who built them are still in business. the Architects are still in business and are easy to find.
Why, a simple call to them will get his answer./ Why must we prove something (we know that is not there anyway) when all he hast to do is make a phone call?
because they are all in on it. they've changed the plans, they doctored the photos and deleted the documentaries. The only evidence left is pictures of dust and Chris' memory.