I remember the impossibly blue sky, and things floating and falling, and cell-phone calls goodbye and the plane hitting the second tower.

But I just couldn't get over what a beautiful fall sky hung over NYC that day, in spite of what happened underneath it. The New York City blue backdrop was so beautiful and fresh and clean in those moments  before the collapse and plumes of black and grey clouds and grit.

New York City is famous for its wonderful museums, of course, so the cartoon of the blue sky hangs on one of the walls.

Cartoon caption of 2 visitors in a NYC museum: "Remember? That's the color of the sky on 9/11." "And we'll never forget all the brave men and women who perished that day."