The Ultra Marathon du Mont Blanc (UTMB) is one of the premier trail events of the year. The race has grown since its inception in the early 2000s and now attracts the best runners in the world and thousands of amateurs. Runners descend upon Chamonix, in the French Alps, for the festival. There are a host of races across the week, with the four main events being the TDS, OCC, CCC and UTMB itself, from Monday August 26 to Sunday September 1. Make sure you don’t miss any of it. UTMB changes lottery system to favour multiple entries; lowers points requirements and introduces ‘running stones’ PTL, 300km, 8am (Central European Summer Time), August 26: The 300km walking race is not a conventional trail race. Participants carry all their gear and navigate across the Alps, with 25,000m of vertical ascent. The first finishers are expected around 2pm on Friday August 30, and the last on Sunday September 1. MCC, 40km, 10am, August 26: This short but sharp race starts in Martigny-Combe in Switzerland and finishes in Chamonix with 2,300m of climbing. It was created for the locals of the area, and the volunteers, so they could be involved in the week’s festivities. UTMB finish line announcer dreams of representing Ireland at Olympics – when he’s not busy selling fudge and teaching English TDS, 145km, 4am, August 28: This race is one of the most technical of the week. It’s the second longest, and has 9,100m of ascents. The winner is likely to finish in around 19 hours. The cut off is 42 hours. It starts in Courmayeur, Italy, and ends in Chamonix. YCC, 15km/8km/4km, 10am, August 28: This race is for the next generation of runners. All the participants are born between 1997 and 2005. The race is near Courmayeur in Italy. OCC, 55km, 8.15am, August 29: The race is short and sharp, but one of the most competitive of the week, seeing participants climb 3,500m as they make their way from Orsiere to Chamonix. The winning time is around 5:30, and the cut-off time is 14:30. Jim Walmsley reflects on Western States 100 record-breaking run as ‘it doesn’t feel like an accident’ CCC, 101km, 9am, August 30: The little sister to the main event, the CCC is ultra competitive. It starts in Courmayeur and closely follows the latter half of the full UTMB race course with 6,100m of ascent. The winner will finish between 10 and 11 hours, and the slowest person has 26:30 to finish. UTMB, 170km, 6pm, August 30: The main event of the week. It starts in the evening, which is unusual for an ultramarathon, but it guarantees two nights out in the hills for many of the runners. The winner will come in around 20 to 21 hours, and the cut off is 46:30. There is a gob-smacking 10,000 metres of ascent. It starts and ends in Chamonix, passing through three countries as the course rounds the Mont Blanc massif.