Thirteen years have passed since the day New York firefighter John Mills' life changed forever.
Then in his early 20s, he was driving home on September 11, 2001, when he heard news that a plane had hit one of the World Trade Centre towers.
Mr Mills' father, 62-year-old Charles Mills, worked for the city's State Department of Taxation and Finance, based on the 87th floor of the South Tower.
"I got back to my house and I called my mom, who worked in the hospital, and was like, 'Mom, a plane hit the tower.'
"She said, 'I know, John. Your dad just called me, he's okay. They're getting out of the building.' And then I watched the second plane hit. I called up my mom again ... and told her a second plane had hit.