old and gray
Ok. I guess I'll kick things off.
People are going to have a hard time convincing me that Yiannis Kourous’ 24 hour record of 188.6 miles (303.506 km) isn't amongst the very best. That's 7:38 per mile nonstop for 24 hours. He also holds the 48 hour record of 294.2 miles (473.495 km) which comes out to be 9:47 per mile for 2 straight days.
I’ve been trying to come up with a way to put those marks in perspective. Here goes my 24 hour analogy.
188.3 miles is more than 7 marathons in a day (7.19). So imagine running a 2:30 marathon, then taking just a 1 hour break and running another 2:30 marathon, then taking another 1 hour break and running another, etc. all the way until you are done with 6 marathons. After your sixth marathon and one hour break, you have to run 31.28 miles at 2:30 marathon pace (5:43.3 mile pace) and you’ll beat Korous time by just 63 seconds. That’s incredible.
I'm now going to go work on a 48 hour analogy.
I think it's widely agreed that Kourous' 24-hour record is one of the strongest, but his Spartathlon record is really impressive as well. If you scroll down to the top 50 performances you can see how much faster he was than anyone else by a long shot.https://en.wikipedia.org/wiki/Spartathlon
This is a 153 mile race, but there is a lot of elevation change if you check the profile, including a 3500' climb - not to mention the heat.