One of the toughest endurance races in the world took place Mexico's Copper Canyon on Sunday (17th July).

It's a true test of mental and physical endurance; with changes of altitude and climate in tough terrain over 100 kilometers.

More than 300 people participated in the famous ultra-marathon race in Mexico's Copper Canyon.

The race is organised by the Tarahumara people, who have run in this region for hundreds of years

It began in the early morning. International runners have been amazed by how some native runners, wearing just sandals and their heavy native clothes, manage to finish the race.

Tarahumarans have the reputation of being among the best long-distance marathoners in the world - tradition says that they used to tackle this terrain bare-footed.

The Tarahumara word to describe themselves, "Raramuri", means "runners on foot" or "those who run fast".

These people developed a tradition of long-distance running - reportedly up to 320 kilometres- in one session, over a period of two days through their homeland of rough canyon country, for inter-village communication, transportation and hunting.

Organisers say every year more people from across the world join the challenge. One thing is for sure- it is certainly not a challenge to be taken lightly.