The Ultra -Trail du Mont Blanc (UTMB) is an iconic route of about 170 km that passes through France, Italy and Switzerland, circumnavigating Mont Blanc with 10,000m of ascent, to be completed in 46.5 hours. Have a look at our short video here.

While the event has a relatively short history, it has already established itself as what many see to be the pinnacle of ultra-trail running. To the non-runner it may seem surprising that people should do this sort of thing for fun. But for many runners, the Ultra-Trail du Mont-Blanc (UTMB) has iconic status, it appears on countless bucket lists and every year runners from around the world make a pilgrimage to Chamonix to take part in the week-long festivities.

About 2300 runners start the UTMB, but in combination with its partner races, the TDS (Sur les Traces des Ducs de Savoie), CCC (Courmayeur-Orsieres-Champex-Chamonix), PTL (Petite Trotte à Léon), and the new OCC (Orsieres-Champex-Chamonix) , a total of almost 10,000 runners come together for the ultimate trail running challenge around Mont Blanc.

Below are the best-known races taking place this week, listed in order of starting times:

Petite Trotte à Léon 290km (PTL)

The PTL is a mostly self-supported run without course markings or aid stations. Runners rely on a limited number of support points, mountain huts, local stores and restaurants for food and sleep. The course should be followed by GPS, maps, and the road book. It goes as high as 3300 metres and must be completed in about 6 days. Each team of two or three people carries a satellite beacon for safety. The course is modified every year and there are no official winners.

Starts: Monday 28^th August 9am at the official Chamonix start/finish point in front of the Church, Place du Triangle de l’Amitié

Finishes: cut off 4.30pm Sunday 3^rd September at the official Chamonix start/finish point in front of the Church, Place du Triangle de l’Amitié

Sur les Traces des Ducs de Savoie 119km (TDS)

Established in 2009 this race takes place in open country along the 'Grande Randonnée' paths crossing though the Mont-Blanc, Beaufort, Tarentaise and Aosta Valley countryside.

Starts: Wednesday 30^th August at 6am, the official starting point is in Courmayeur at Piazza Brocherel

Finishes: first finishers 8.30pm Wednesday 30^th August, cut off 3pm Thursday 31^st August at the official Chamonix start/finish point in front of the Church, Place du Triangle de l’Amitié

Orsières Champex-Lac Chamonix 57km (OCC)

Established in 2014 the OCC is perfect for fans of medium (Ultra) distances, for those perhaps wishing to enter the UTMB race itself in the future.

Starts: Thursday 31^st August at 8.15am the official starting point in Orsières Place Centrale

Finishes: first finishers 1.30pm Thursday 31^st August, cut off 11pm Thursday 31^st August at the official Chamonix start/finish point in front of the Church, Place du Triangle de l’Amitié

Courmayeur-Champex-Chamonix 101km (CCC)

Established in 2006 the CCC has climbed from being the "little sister of the UTMB" to becoming a unique race that is one of the most prestigious in the world. Being a CCC finisher allows you to be classified on the Ultra-Trail World Tour (UTWT) 2017 points sheet.

Starts: Friday 1^st September at 9am, the official start point is in Courmayeur at Place Brocherel

Finishes: first finishers 8pm Friday 1^st September, cut off at 11.50am Saturday 2^nd September at the official Chamonix start/finish point in front of the Church, Place du Triangle de l’Amitié

The classic original UTMB 171km

Established in 2001 this route basically follows the Tour du Mont Blanc hiking path, that is usually completed in 7 to 9 days by hikers around Mont Blanc.

Starts: Friday 1^st September at 6pm at the official Chamonix start/finish point in front of the Church, Place du Triangle de l’Amitié

Finishes: first finishers 3pm Saturday 2^nd September, cut off 4.30pm Sunday 3^rd September at the official Chamonix start/finish point in front of the Church, Place du Triangle de l’Amitié

See the full timetable of events on the UTMB website here

Keep your eyes peeled for the official favourites chosen by and published in this year’s UTMB 2017 programme: