The same organization has one here in NYC that is nearly 5000km, running around a single block in Jamaica, Queens, over the course of 52 days: https://en.wikipedia.org/wiki/Self-Transcendence_3100_Mile_R...

For anyone in the northeast, i can recommend Three Days At The Fair [1], the longest duration of which is actually 6 days and the course is a 1 mile loop around a state fair ground in New Jersey. I did a mere 12 hour option on the final weekend, and the suffering of those competitors on their 5th/6th day is something i will never forget. Sideways leans, some quite pronounced, others moving backwards to alleviate pains developed moving forwards etc.

Why do they do it? Well, the camaraderie is incredible. Much of the course is lined where runners have pitched their tents/campers/chairs and the support, sharing of food, stories and beer make it a unique event. The shortest duration is 6 hours and you’re not obliged to run more than a single loop/mile if you don’t want to.

[1] - https://sites.google.com/site/njtrailseries/fair

Reminds me of Beau Miles' "24 marathon" which was much more fun: https://www.youtube.com/watch?v=EvT5XS7j-Dc&t=6s

Relatedly, see Big's Backyard Ultra[0]: runners run a 4-mile loop, on the hour, every hour, 24 hours a day, until only one runner completes a loop that nobody else does. In 2011, when it started, the winner did 18 laps. In 2023, the winner completed 108 laps!

[0]: https://en.wikipedia.org/wiki/Big%27s_Backyard_Ultra

> it's the most pure running format.

Pro-tip: stay clear from anyone who makes these comments. Someone sold them a philosophy and they are too financially deep into it to back down.

On skateboards, it's called an Ultraskate: https://24hourultraskate.com/

A 24-hour party of pain - a day and night running round a track