Transcript for 9/11 Mystery Unfolds as Airplane Piece Found Blocks from Ground Zero
Now to that stunning find in new york city we first reported last night on "world news," a piece of one of the planes that hit the twin towers on 9/11 found in an alley in downtown manhattan wedged between two buildings. Tonight many asking how could no one have noticed this, more than a decade after 9/11. Reporter: Just a few blocks from ground zero sits what's believed to be landing gear from one of the hijacked jets that crashed into the world trade towers. Such a long period of time I'm amazed by what is discovered right now. Reporter: Wedged between two buildings in a narrow alley. It hasn't been touched in more than a decade. The space begin the buildings is only 18 inches. The part is measured to be five feet by four feet by 17 inches. Reporter: Authorities say it was found wednesday morning by workers doing construction on a controversial islamic center. If you see how confined this space is and realize the chaos that existed on this street, it's understandable. Reporter: Authorities don't know how it got there. If you look closely you can see a rope attached to it. Could it have been lowered some time? It's possible. We look to see if there are marks on the wall. There doesn't appear to be marks on the wall. Reporter: With so many unanswered questions authorities will take their time combing through the rest of the area for other debris or human remains. Could there be remains of victims inside? We'll do an in depth examination of the site. Police are guarding the entrance to the alley because this is now considered a crime sce and because it could be this remarkable discovery.
This transcript has been automatically generated and may not be 100% accurate.