The 21st annual Daytona 500, run on Feb. 18, 1979, at Daytona International Speedway, launched a multi-year journey that saw NASCAR stock car racing transition from a regional phenomenon into a mainstream American sport.

With CBS televising the 500- mile race flag-to-flag for the first time, auto racing got its first “water-cooler moment” as viewers gathered at work the next day to talk about the race’s dramatic final lap – and the fight that followed.

Donnie Allison led the way as the white flag waved with Cale Yarborough drafting closely behind. Going down the back straightway, Yarborough attempted to pass Allison on the inside, but Allison drove low to block. Yarbrough eventually ran out of asphalt and the two cars tangled and crashed after Yarborough lost control when his left-side tires were on the infield grass.

As Allison and Yarborough’s wrecked race cars slid to a stop inside Turn 3, Richard Petty swept by the carnage with Darrell Waltrip on his rear bumper. Petty held off Waltrip to record his sixth Daytona 500 victory.

CBS announcers Ken Squier and David Hobbs were recapping the final moments when Squier said, “And there’s a fight between Cale Yarborough and Donnie Allison.”

The cameras immediately zoomed in on the fracas as Allison and Yarborough, along with Bobby Allison who had stopped to check on his brother, vented their frustrations.