Winner of the last five Tours he participated in (he skipped the 1973 edition), Eddy Merckx entered the 1975 Tour as the clear favorite. But this would be the year Merckx, arguably the greatest cyclist of all-time, would get dethroned for good. And boy, did it come about via a most bizarre string of events.
During the 14th stage, which would finish atop the Puy de Dome, Merckx had the overall race lead and was about to catch the other race favorites when a spectator jumped from the crowd and punched Merckx in the kidney. Merckx, losing precious time to the other general classification contenders, eventually stumbled across the line vomiting. Despite this, Merckx still rode down the mountain to identify the man who threw the punch.