Badwater  is a 135 mile ultramarathon from Death Valley, the lowest spot in the USA, to Mount Whitney Portal near the highest point of the 48 states. Besides the elevation gain and the distance, extreme temperatures make the Badwater 135 an extreme challenge. Running on the Sun is a documentary film of the July 1999 event. It's both inspirational and fun (OK, if you're a trail runner) to see feet decorated with blisters, people vomiting and hallucinating as they plod day and night, toes without nails, etc. The participants in Badwater are awesome in their determination — though in some cases, also quite foolish as they persist in the face of injury.
And there's humor. One assistant explains that his job, to crew, is an acronym for "Cranky Runner, Endless Waiting". Best of all is 68-year-old Ephraim Romesburg, interviewed on the road at mile 65 of Badwater, as he presents a perfect mission statement:
I always start these events with very lofty goals, like I think I'm going to do something special. And after a point of body deterioration the goals get evaluated down. I always get to a point, which is basically where I am now, where the best I can hope for is to avoid throwing up on my shoes.