NEW YORK (CBSNewYork) — The most devastating attack by a foreign enemy against the United States now has a new angle.

The National Institute of Standards and Technology obtained a recording of the September 11, 2001 terror attacks. The NYPD helicopter video spans from shortly after the impacts of American Airlines Flight 11 on the North Tower and United Airlines Flight 175 on the South Tower, to minutes after the Towers collapsed.

Related: Remembering 9/11 – Archival Footage

The pilot flew the police chopper around the Towers, surveying the damage from multiple elevations and vantage points, before setting the aircraft down.

“It’s gone! The whole Tower! They knocked the whole friggin’ thing down!” one officer on board said as he watched the carnage from a cabin window.

After landing, that same officer was asked if he got the Tower shot. His answer: “Right after it. I had it going. I moved over and got the smoke.”

“That’s it. That’s the biggest disaster in the world. Right there,” he later said.

“Be advised the Tower is down. All personnel be advised the North Tower is down,” another officer radioed.

The NIST is part of the Department of Commerce and tasked with promoting “U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.”

The agency obtained the video via a Freedom of Information Act request and conducted an investigation of the September 11 attacks, which began on August 21, 2002.

Its goals were to develop “improvements in the way buildings are designed, constructed, maintained, and used; improved tools and guidance for industry and safety officials; revisions to building and fire codes, standards, and practices; and improved public safety.”

The agency was also responsible for investigating the domestic terror bombing of the Oklahoma City Murrah Federal Building in 1995, and the first attack on the World Trade Center in 1993.

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