The Badwater Ultramarathon is a 135-mile ultramarathon through the Californian desert which claims to be so intense as it tracks from the lowest to the highest point of the contiguous United States. Not only does the course include 13,000-ft (4,000m) of cumulative elevation gain, it takes place in mid-July when temperatures can rise to up to 54 degrees Celsius.
The course goes through the treacherous salt flats of Death Valley making it one of the toughest foot races in the world, and each racer must have a support crew and vehicle due to the risks of dehydration. The original course included a punishing climb to the summit of Mount Whitney which is the USA's highest point, but after the US Forest Service started requiring permits to climb Mount Whitney, the course was changed to end at Whitney Portal.
The Badwater Ultra marathon is so prestigious and extreme that it is invitation only, and athletes must be able to prove their worth before they can enter. There is a 48-hour time limit, so it is not for the faint-hearted. The British record is currently held by Dan Lawson, an ultra runner who has an impressive number of titles to his name.