Tribute in Light is a beaming installation that millions have come to expect to see each year at dusk on the 11th, but these brilliant lights may soon dim.
It's not guaranteed after this year because, Vin Cipolla says, his agency just learned it will not receive a huge chunk of money needed for this project.
He heads up the Municipal Art Society, which produces the memorial.
The lights costs about 500-thousand dollars, 12 days of set up and crews meticulously testing each light before officially flipping the switch.
The money comes from several places - private donors and the Lower Manhattan Development Cooperation, which kicks in the bulk of the money.
Now, Cipolla must look for the money someplace else.
One plan on the table is a way to significantly cut down cost is to make the lights, which right now have to be set up and broken down each year, a permanent part of Lower Manhattan.
On a clear night you can see them from more than 60 miles away. The two extraordinary beams have illuminated such a dark place.
"Memory is so short for most people it's worthwhile recollecting what it was for people, how traumatic it was for the whole nation," Cipolla said.
The Municipal Art Society has started a public campaign to raise money for this project. People can text the word TRIBUTE to 20222 to make a donation of 10 dollars toward this project.