Despite 9/11 occurring during post-production, Scorsese refused to change the final image depicting the Twin Towers.
As Scorsese put it;
“We did the paintings and edited that skyline sequence before September 11, and afterward it was suggested that we should take out the towers, but I felt … it’s not my job to revise the New York skyline. The people in the film … were part of the creation of that skyline, not the destruction of it. And if the skyline collapses, ultimately, they will build another one.”