What is the best sporting moment of all time?

Kirk Gibson’s walk-off homer in the ‘88 World Series.

https://m.youtube.com/watch?v=N4nwMDZYXTI

For context, Gibson injured both legs (left hamstring and right knee) during the playoffs and it was unclear if he could even hit the ball. He wasn’t even planning on playing that day and was doing physical therapy during the game with the broadcast on in the background. Vin Scully (the commentator) remarked that he was “nowhere to be found” and that motivated him to suit up and tell the manager he was available to pinch hit.

You can see during his at bat how weak his legs are — his legs shake visibly and he stumbles after his swings. Moreover, he’s facing a future hall of fame pitcher. Nobody expected he’d be able to hit a home run, the manager was just hoping he’d hit a long single to tie the game. However, Gibson knew, thanks to the coaching staff, that the pitcher had a favorite pitch when the count was 3-2 and he crushed the hell out of it.

That's going to depend on what sports each individual is interested in. For university level football in the US, probably a tie between "The band is on the field" and the Kick Six. Even then, most fanbases have their own version of the best moment ever ("trouble with the snap"), even if not many outside of their fandom agrees.

MJ’s last-second shot to win Chicago’s 6th NBA title against Utah.

I'm going to add Laird Hamilton towing in to Teahupoo 17 August 2000. While it has since been exceeded or replicated, at the time this was a big step above what anyone else had ever done. Most mere mortals (like myself) didn't even know a wave could do that, let alone be surfed. It was as if the entire ocean decided to shift 30 ft in the air before detonating on the reef. Here it is:

https://www.youtube.com/watch?v=T8HCF2cef74

(The wave at 2:46)

Surfer magazine ran it on the cover that month with the caption "Oh my God ..." https://northshorehawaii.wordpress.com/laird-hamilton/

The surfing world was forever changed.

For me, it's Randy Johnson's bird hit. A bit morbid, but the just incredible timing and impact is just mind boggling. https://www.youtube.com/watch?v=Ih_ovjbwQGk

Not significant from a situation/narrative perspective, but Roberto Carlos’ impossible goal always comes to mind https://youtu.be/ZnXA0PoEE6Y

I still cannot get over Michael Phelps' 8 gold medals in 2008 Beijing Olympics

That time Buck Shelford, in his first test match, got his nut sack ripped open. He got the physio to stitch it back up and kept playing (until he was concussed and taken off).

The rumble in the jungle. Ali vs. George Foreman, 1974.

https://youtu.be/9bRiFEvxlp8

Leicester City winning the English Premier League in 2016. 5000:1 odds. The season before they had been fighting relegation.

I'm from South Africa, so I've always been captivated by the South African season/win at the 1995 Rugby World cup and the political context of it. Dramatized in the movie Invictus.

I don't know if it's the best sporting moment of all time, but it's certainly an interesting one.

Donovan Bailey 100m meter olympic record. He was behind almost everybody and passed them all: https://www.youtube.com/watch?v=W7_NCGWvOcI

For me it's the miracle on ice but I grew up in hockey obsessed New England. I'd also throw Tiger winning his first Masters up there.

The more accurate answer is probably something akin to Jackie Robinson but that was before my time.

Shane Warne's ball of the century is up there and I'm not even an Australia fan: https://www.youtube.com/watch?v=s3V-sYH0Sks

Tyson biting off Holyfield’s ear. Not the best but memorable.

The Play https://youtu.be/AfIi0uBMNBI

'92 Olympic Dream Team (US) in basketball. Asking anybody to play against them was pushing the boundaries of ethics.

Red Sox 2004 postseason comeback, Kick 6 Auburn vs Alabama college football.

no doubt Jesse Owens at the 1936 Summer Olympics

India winning World Cup of cricket