The specific and credible, though unconfirmed, threat involves a vehicle bomb aimed for sometime between September 10 and the 12, with either Washington DC or New York City as the target. The plant also involved three individuals and at least one of them is a U.S. citizen.
That threat comes as people in New York City prepare for this Sunday's 9/11 commemoration ceremony.
Just beyond this gate, thousands of workers are feverishly finishing up to be prepared for 9/11 10th anniversary. There are so many reflections and remembrances on this day.
Images of that horrifying day are so close to the surface -- the smoke, the collapsing towers, the ash, people desperately trying to get away to anywhere.
Ten years ago, I reported from this dreadful site. Today, there is an amazing transformation with construction booming for a new World Trade Center complex.
"Already it is the tallest building in New York and it's on its way to being the tallest building in the Western Hemisphere. From the very top, you'll be able to see the curvature of the earth," said Bill Baroni of the NYC Port Authority.
But if there is one site in the world that terrorists want to strike, it is this 16-acre site.
The new, detailed and incredible threats about a possible vehicle bomb have these visitors from Belgium extremely nervous.
"That is why we're coming today and we won't come back on the 11th," said tourist Natalie Teenigf.
Some are fearful, others fearless. They want nothing more than to visit Ground Zero to pay their respects and to remember.
Right next to the WTC is St. Paul's Cathedral. All of these bright ribbons line the church with messages written on them.
"I think it's a beautiful remembrance of the day and how this church was basically the only building standing in this area. It's surreal. I think it's really surreal when you stand here, " said New York resident Kathy Custer.
There are so many symbolic remembrances of that day 10 years ago.
The new World Trade Center skyscraper is now 80 stories tall. They are adding about one floor per week.