Sunday marks the 15th anniversary of the terrorist attacks on the World Trade Center and the Pentagon. On the day after those 9/11 assaults, Variety ran the headline “The Mourning After,” with multiple stories about the shocked and horrified reactions from New York, D.C. and around the globe.

One New York-based exec said the city was in “a state of silent shock.” However, he added, “Amid all the chaos, there was a gentleness”; volunteers rushed to the scene, neighbors were helping each other, and even subway riders showed quiet good manners.

The crisis situation inspired gentleness in many other areas. Networks pooled many of their news resources, saying it would be foolish to be proprietary and competitive at a time like this. A CBS News spokesman said, “In the history of broadcast journalism, this is unprecedented.” Many businesses in New York and Washington sent employees home, all 23 Broadway shows were canceled and even many London companies allowed workers to leave early, to watch TV coverage.

Among the many canceled showbiz events were the Emmys, which had been scheduled for Sept. 16. According to the Variety Archives, producer Don Mischer said, “This is a national crisis and no time to be handing out awards and comment on what people are wearing.”

After the second plane hit, the Federal Aviation Administration’s Ben SlineyCQ — in his first day on the job as national operations officer — indefinitely grounded all flights over U.S. airspace. About 4,500 flights were affected. Among those stranded were attendees at the 26th Toronto Film Festival, which ran Sept. 6-15. The fest cancelled 28 screenings that day, and festival executives worked to find lodging for the many individuals who were scheduled to leave but couldn’t.

The U.S. received support from around the world, including French President Jacques Chirac, who said, prophetically, “No country in the world has ever before been the target of such violent terrorist attacks … What has happened in the U.S. concerns us all.”

People in show business wondered: When is it appropriate to get back to work, to resume “normal” entertainment? David Letterman addressed that question in an eight-minute serious monologue when his late-night talkshow returned to the air one week later. “We don’t know how to behave; we’ve never been through this before,” he said. He quoted Mayor Rudy Giuliani, who encouraged people to return to their jobs and their lives, to demonstrate courage and determination to the rest of the world, including the terrorists. “Because of him, I’m here tonight,” said Letterman.

Letterman’s guest Dan Rather discussed 9/11 and its long-term implications, saying the terrorists were “a hydra-headed operation that’s in 55 countries around the world.” Rather choked back tears twice, and broke down while reciting lyrics to “America the Beautiful.”

Regis Philbin was sitting in the Green Room, ready to follow Rather. Philbin saw Rather choke back tears and later admitted to Variety “I wondered ‘What am I doing here?’ I freaked out.”