Located on the French side of the mountain, the north face is one of the three great north faces of the Alps, along with the north faces of the Eiger and the Matterhorn (known as 'the Trilogy'). One of the most famous walls in the Alps, it towers 1200 m (3,900 ft) above the Leschaux Glacier, stretching 1 km from end to end. The classic route on the face is the Walker Spur (Cassin/Esposito/Tizzoni, 1938, TD+/ED1, IV, 5c/6a, A1, 1200 m) which leads directly to the summit of Pointe Walker. The other major buttress on the mountain is the Croz Spur, which leads to the summit of Pointe Croz. In her solo ascents of the six most difficult north faces of the Alps, Alison Hargreaves chose this route in preference to the Walker Spur.