https://www.youtube.com/watch?v=tnXjdv_GM9g
http://deadspin.com/the-story-behind-bob-beamons-miracle-jump-and-the-only-1736766124
This has happened in the 1968 Olympics in Mexico City

 ................ Officials had installed an electronic measuring device that ran 

on a rail alongside the pit. The judges moved the optical sight to the point 

where Beamon landed — out, farther, out some more – until it fell off the 

far end of the rail. They hurried off to find a measuring tape.

Some 20 minutes passed as the officials checked and double-checked the 

distance. Finally, three numbers were posted on the scoreboard: 8.90.

It was the distance of the jump in meters, and Beamon did not realize 

what that was in feet and inches. Boston informed him it was beyond 

29 feet–and Beamon collapsed onto the track..."