(CNN) -- Newly released photographs show what a damaged World Trade Center tower and its collapse looked like from a New York Police Department helicopter as it flew nearby on September 11, 2001, in New York.
The aerial photos were obtained by ABC News after it filed a Freedom of Information Act request last year with the National Institute of Standards and Technology, which had collected the images for its investigation into the towers' collapse.
A couple of the images show one of the twin towers burning after a hijacked airplane had flown into it. Others show it collapsing, and the rest show the clouds of debris and dust spreading below after the towers crumbled.
Each of the 12 images offers a rare look at what the devastation looked like from above.
Hijackers flew two commercial jetliners into the twin towers that day, killing 2,752 people. On the same day, hijackers flew another airplane into the Pentagon in Washington, killing 184 people. A fourth hijacked plane, headed to an unknown target, crashed in Shanksville, Pennsylvania, killing 40.