As an American I think the clear answer is the 1980 Olympics when our hockey team defeated the Soviets (the Miracle on Ice).
The one that always sticks in my mind is Kerri Strug nailing the vault on an injured foot and immediately breaking down.
W2002 - Steven Bradbury Winning Gold, S2000 - Cathy Freeman Winning Gold and 4x100m Freestyle Relay Gold.
As an American, Miracle on Ice is obviously the answer for us.
In 1960 Rome Olympics, Abebe Bekila ran marathon barefoot and won Ethiopia’s first OLYMPIC gold. He is regarded as a national HERO.
Mike Eruzione goal
Far before my time obviously, but I think it’s hard to beat Fanny Blankers-Koen’s quadruple gold at the 1948 London Olympics.
For my country Morocco, without a doubt Hicham El guerrouj the lengadry 1500m runner and his epic double gold medals in Athena 2004 (1500m and 5000m).Hicham had terrible fall injury in Atlanta olympics1996, then got a disappointing second in Sydney 2000 despite being favorite and world record holder. He didn’t give up and tried for a final try in Athena 2004 despite being past his prime and he won a miraculous double gold medal both in his specialty 1500m and a bonus gold in 5000m!
Spain, Barcelona '92, greatest torch lightning in history.
Czech republic. Nagano. Our hockey team won gold.They let NHL players play and USA and Canada were planing to be in final. Hasek was our hero.
Sidney Crosby scoring the Golden Goal in the 2010 winter Olympics on home ice in Vancouver. You would be hard pressed to find a Canadian who doesn’t remember exactly what they were doing when that goal was scored.
Jessie Ownes
Zola Budds epic BAREFOOT slide tackle against Mary Decker.
Donovan Bailey’s 1996 WR 100m 9.84s is pretty high up there.
1956 waterpolo game against the Soviets.
Kelly Holmes’s double Olympic gold.