Where are the most difficult ski runs in the Alps?

Where are the most challenging slopes in the Alps for skiers? According to a new study, the Sarenne in the French Alps resort of Alpe d'Huez is the toughest of all.

The piste is located at an altitude of 3,330m and at 17,000m, it is the longest black run in the French Alps.

The 2,900m Face de Bellevarde (pictured above) in Val d'Isere, is also one of the toughest. With a 972m vertical drop, it requires skiers to be quick-thinking on the piste. The reward? Panoramic views of Val d'Isere.

The Swiss Wall in Avoriaz is another extreme ski slope: skiers cannot see the face of the run from the top as it is so steep.

Luxury ski agent SkiBoutique has compiled the list of the top ten toughest ski slopes for those looking for a challenge on their next ski holiday. The list includes Mont Fort in the Swiss Alps, known for the bumps along the 1,750m run which make it a tricky piste to master, and Austria's steepest run Harakiri in the Zillertal Alps, which was named after the Japanese ritual samurai suicide.

Want to know which slopes to add to your extreme holiday bucket list, or the ones to avoid? Check out more of the Alps' most gruelling ski runs, with fun facts and stats in the infographic below.