Warning: Some readers may find these photographs disturbing.
In the early morning of September 11, 2001, photographer David Monderer stood on the pedestrian walkway of the Manhattan Bridge and peered through the viewfinder of his camera. For weeks, Monderer had been waiting for the perfect morning to photograph the skyline. He'd arisen that morning and, seeing that the weather forecast was sunny, decided this was the day. One of his first pictures, taken at approximately 8:30 a.m., captures the skyline just as Monderer had hoped: fully illuminated by the sun behind him, no shadows cast across it. He kept taking pictures and, soon after 1 World Trade Center was struck by a plane at 8:46 a.m., he took more.

This slideshow begins with Monderer's first photograph from that morning. The series also includes later photographs of the Manhattan skyline.

You can see more photos from Monderer's series here.