12. Dragons Back Race
Source: Iconosquare
Wales–This race was created in 1992, and is one of the hardest mountain races in the world going through the Welsh countryside from Wales to Carreg Cennen Castle. The next one comes up in June 2015, takes 5 days to complete, and is around 300 kilometers. This race is not for the weak, it very specifically says on their website what kind of extreme racing experience you need to have to be able to have a shot at doing the Dragon’s Back Race. It also cost a pretty penny to enter with fees being around $700 bucks.