The only known aerial photographs of the World Trade Center as it collapsed on Sept. 11, 2001, were released by ABC News on Wednesday.
The photos, taken from a helicopter by New York Police Det. Greg Semendinger, show the twin towers in flames, falling amid huge, billowing clouds of dust, debris, and smoke that envelop downtown Manhattan.
The 13 photographs were among thousands of pictures that ABC News sought under the Freedom of Information Act from the National Institute of Standards and Technology, which investigated the collapse of the towers, agency spokeswoman Gale Porter said.
Although other photographs of the falling towers were taken on Sept. 11 from satellites, rooftops, and other aircraft, these photos are the only ones known to have been taken up close from an aircraft flying overhead in city airspace.
Nearly 3,000 people died when hijacked airliners crashed into the towers.
The aerial photographs had been partially published in the past but now are publicly available to researchers.
"With these pictures, you move from a specific slice of information to much greater context," said Jan Ramirez, chief curator at the National September 11 Memorial & Museum.
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