For many years it seemed like running 26.2 miles in one hit was was more than enough for most people. For armchair runners it was almost superhuman. Nowadays you can’t help but be overwhelmed by the amount of marathoners there are out there. Every man and his dog seems to be entering one for charity.

The rise in popularity of the marathon over the past few decades has led to the natural search by runners looking for the next big challenge. And so the ultra distance race has become the yardstick to measure yourself against others by.

Strictly speaking an ultra is anything longer than a marathon which that can mean anything from 50km right up to 200miles. Difficulty depends on the terrain depends on the terrain and conditions as much as the distance.

Here is a selection of some of the toughest of their kind in the world right now.