To note: horses compete alongside humans... while carrying a human.

Very cool. I'd like to see a horse vs human ultramarathon, more like the 24 hour time the parent suggested. I was surprised human and horse competitors were so close at that distance!

tl;dr: Annual 22-mile race with both pedestrian and equestrian competitors. Out of the 40 times it's been held, the winner was a human twice, and a horse 38 times. Typically the spread between the fastest human and the fastest horse has been less than 10 minutes.