While serving in the Army as a member of Alpha Company, 3rd US Infantry, Adam Eisenberg spent approximately 240 hours on site, with at least a hundred of his fellow servicemen, at the Pentagon on 9/11.

In short, he helped clean up the mess from the plane crash.

Except that, well, there was no plane, he argues.

Adam's job was to move debris and haul away wreckage, which means he was looking for wreckage, and what he found instead was office paper, furniture, and building rubble, with barely a scrap of aircraft in sight.

A Boeing 757 is about 38 metres wide, yet the hole in the wall was roughly 5 metres across before the façade collapsed.

No wings, no tail, no landing gear, and the lawn outside, where a 100-tonne plane supposedly skimmed the ground at over 800 km/h, was pristine.

The one piece of engine photographed on that lawn has been hotly debated, with some arguing it matches a 757 component and others, including analysts who compared it to the CFM56 engines Flight 77 was fitted with, insisting it comes from something much smaller.

In other words, it was placed there.

It's a single part standing in for an entire missing aircraft. A jet with 64 passengers and crew allegedly slammed into that section, yet Adam and his unit spent 240 hours hauling out mostly office debris.

Where did everything go?