1997
Kasparov vs Deep Blue
When calculation became theatre.
Kasparov beat Deep Blue in Philadelphia in 1996, four games to two. IBM rebuilt the machine and came back a year later.
In the 1997 rematch in New York, Deep Blue took the match three and a half to two and a half. Kasparov resigned the final game after nineteen moves. He questioned how the machine had played; IBM declined a further match and retired it.
The result mattered less than the framing. A calculation had been staged as a contest, and the audience watched it as one.