What does achieving a Grand Slam mean across different sports?

#9 Ultra Running

Annual Badwater Ultra Marathon Held In Death Valley's Extreme Heat

An Ultra Race is any foot race which is longer than the traditional marathon length of 42.195km (26.219 miles).

To win a grand slam of Ultra Running, a person has to complete three out of four of the oldest 100 miles trail runs in the United States in the same year. The races are the Old Dominion 100 Mile Run, the Western States 100 Mile Endurance Run, the Vermont 100 Mile Endurance Run and the Wasatch Front 100 Mile Endurance Run.

Tom Green was the first runner to complete the Grand Slam of Ultra Running. In the present time, about a dozen runners complete the Grand Slam each year.