10. Fat Dog 120
Source: Iconosquare
Canada–Described as one of the most scenic races in Canada, this race comes up in August 2015 with runners that only number 225 people. It’s a good combination of trails, and more rugged terrain for variety. There is a river crossing during the race, and the sponsors provide ropes to help competitors get across. If you make it through all 120 miles then you are definitely an extreme athlete.