Dozens of photographs taken by the New York City Fire Department and newly released by the government provide a sobering reminder of the conditions at ground zero in the aftermath of the Sept. 11, 2001, terrorist attacks on the World Trade Center.
They show, among other things, firefighters climbing atop the massive piles of rubble in darkness, hours before large generator-powered lights were brought in to the scene. Some photos offer a close-up look at the massive debris filling lower Manhattan streets. Others show the thick gray ash and countless pages of white office paper that settled over the devastated area.
"We all have particular photographs seared into our visual memories, but this is progressive drama – it's breathtaking in the most horrific way," said Jan Ramirez, chief curator of the National September 11 Memorial and Museum. "It's very important for people to be able to see this."
Click here to watch Jan Ramirez narrate the 9/11 images.
ABCNews.com first published a small sample of the collection that included aerial photos taken by New York City Police Department helicopter pilot Greg Semendinger. A second set of Semendinger's images was released earlier this week.
The rare aerial shots offer a visual narrative of Sept. 11: tugboats and commuter ferries racing to the shoreline near the burning twin towers, the dust and debris plume engulfing lower Manhattan, and the blanket of ash that covered the ground.
Many of the shots are from angles and perspectives not widely seen before.
"They're exceptional," Ramirez said in an interview with ABC News. "When you see this aerial body of work, you are given the rarest overview quite literally of this event as it's transpiring over the full 102 minutes and rest of the day."
The images taken by firefighters on the ground in the immediate aftermath of the buildings' collapse are particularly compelling for their intimacy with the surreal landscape and the level of detail they provide. The streets around the destroyed towers are choked with ash and paper.
"We look at that dust now for an entirely different view of what it represents," said Ramirez. "[It represents] the people that would never come back and, sadly, the health consequences it also caused for thousands of people who came to help thereafter."