[masraum]

Originally Posted by DonDavis

There are many. Talk about a rabbit hole of a search.

https://ultra-x.co/best-and-toughest-ultra-marathons-in-europe-2020/

There's some old photos on the site below. There are 9 books from which each runner must tear out the page number that corresponds to their bib number. It proves each runner made that checkpoint. The books are named appropriately.
"A Time to Die" was one. Another was "Southern Discomfort".

The Barkley Marathons

The "Tour of Giants" looks pretty insane, but still, it appears as if people finish it.