In the afternoon of May 4, 1971, in the Stouffer's Somerset Inn in Shaker Heights, Ohio, Steve Cook presented his STOC paper proving that Satisfiability is NP-complete and Tautology is NP-hard.
The theorems suggest that Tautology is a good candidate for an interesting set not in [P] and I feel it is worth spending considerable effort trying to prove this conjecture. Such a proof would be a major breakthrough in complexity theory.And thus Cook formulated what was soon to be called the P versus NP problem. The rest is history.
Here's the 1971 STOC Program (there were 143 attendees) and what that sacred ground looks like today.