While the nation remembers the terrorist attacks that killed thousands of Americans 20 years ago, New York City firefighters, sent to rescue victims at the World Trade Center who survived, will relive a life-changing experience that's now a part of who they are. "It's a day that will never leave you," Fire Department of New York Commissioner Dan Nigro tells Scott Pelley. Nigro and other firefighters at Ground Zero, many of whom fill the top ranks of the FDNY, recall the men, their sacrifices, and the tragedy of losing 343 of their colleagues on the 54th Season Premiere of 60 MINUTES. This one segment runs the full hour.

The Facebook Whistleblower – A former Facebook employee says tens of thousands of pages of internal company research she has provided to the Securities and Exchange Commission and investors prove Facebook is lying to the public and investors about the effectiveness of its campaigns to eradicate hate, violence, and misinformation from its platforms. That former employee reveals her identity and speaks her mind with Scott Pelley. 

Unforgiven – The Public Service Loan Forgiveness Program was meant to wipe clean students' loan debts in return for a decade of public service. In theory, many military borrowers could benefit from this. But in practice, it hasn't panned out that way. Lesley Stahl talks to a group of military lawyers who had accrued law school debt and hoped for relief in exchange for their service but say they got lost in a maze of rigid rules and red tape. 

The Final Act – Tony Bennett has Alzheimer's disease. It's taken a toll on his memory, and the 95-year-old singer has trouble holding a conversation. But when the music comes on, the legendary crooner is able to break through the fog to find his voice again. Anderson Cooper and 60 MINUTES cameras were at a final performance he gave with Lady Gaga to capture the moment.