In a previous post, my colleague B.J. Schecter has asked whether the performance of Usain Bolt at these Games has been more impressive than that of Michael Phelps. (I'm with B.J. on tabbing Phelps.)

I'd like to add a question that takes a longer view. There are certain Olympic results that have come seemingly out of nowhere and whose aftershocks have altered the landscape. Bolt's strikes me as belonging on that list. I was amused in my colleague Tim Layden's story yesterday previewing the 200 as to how many of the old-timers didn't seem to think Bolt had paid his dues; that how a guy who hadn't been around that long and had such an unconventional style (mostly because of his height) would have to get a little more seasoning before he could lower the record. Clearly, that conventional wisdom has been turned on its head.

Here are some other summer events in my Olympic lifetime that made everyone sit up and take notice.

1. Abebe Bikila of Ethiopia winning the marathon at Rome in 1960, essentially putting Africa on the track map.

2. Bob Beamon of the U.S. obliterating the long-jump mark in Mexico City in 1968.

3. At those same Games, high jumper Dick Fosbury of the U.S. introducing the "Fosbury Flop."

4. The Soviet Union ending the U.S.'s men's basketball dominance at Munich in 1972.

5. The perfect 10 on the uneven bars by Romanian gymnast Nadia Comaneci at Montreal in 1976.

6. Ben Johnson being stripped of his medals after the Canadian sprinter was found to have been on Stanozolol while winning the 100-meter dash in a world record 9.79 at the 1988 Games in Seoul.

What other summer events would you say have had such seismic impact? And where does Bolt rank on the seismic scale?