The well-known French guide Gaston Rébuffat must have really linked this, sunny side of the Aiguille du Midi. He was the climber who opened up both of these now popular and classic alpine rock climbs. He first climbed the South Face of the Aiguille du Midi on July 13, 1956, and Eperon des Cosmiques one month later on the 13th of August.

These routes became well-known and quite popular very quickly. For many, ourselves included, perhaps the most enjoyable kind of climbing is found on sun-warmed rock, high about wild crevassed glaciers. The rock on these climbs is excellent golden granite, rough and textured, but monolithic with big slabs cut by long cracks.

These are day climbs, easily done from a base in Chamonix by taking an early cable car. However, the nearby Cosmiques hut allows climbers to stay up high, and do any number of great day climbs at a more relaxed pace from a hut base.

The Rébuffat route is the most classic of the many routes on the South Face. It is moderately long, about 10 pitches, with many in the 5.8 to 5.9 range. The crux section is mid-5.10, but short. Most climbers aid their way through this steep bulge. Higher, the "S" crack gives continuous 5.9 climbing with a thin crack splitting an immense slab. There are many strategies that climbers adopt to do this route. The more ambitious will climb from the bottom of the route, carrying their boots, crampons and packs from bottom to top. Others, more conservative, will leave packs at the base and descend the route by rappel. And other, bolder, climbers will start at the top, rappel the route, then climb back up to the summit and the cable car back to town.

The Eperon is somewhat shorter and easier than the South Face. But even it has some hard climbing, particularly at the steep roof at one-third height (usually climbed wit the aid of fixed gear, conveniently placed for the hands at the crux). The route is perhaps about 6 pitches in length, and finishes on a small summit-spur ridge of the Arête des Cosmiques. Most climbers will leave boots and packs at the base, then rappel the route (or actually a nearby line) to retrieve their gear. However, it is also possible to carry boots and packs up the route, and finish the climb of the Midi via the Arête des Cosmiques. After a couple easier pitches at the start, a steep pitch leads up to and over a roof to a good stance above. The roof is about 5.10c-d if climbed free, but a few aid points bring this down to an easier rating of about 5.8. Above, two more steep 5.8-9 pitches leads to easier climbing just below the small summit.