Louis Lachenal made his first ascents on the Biclope rock in 1934. An assiduous choir boy, he preferred the world of the street to school benches. His taste for risk and the search for danger will be for him a sort of ideal of life. Thus, at the age of 13, his vocation called him to the mountains surrounding Annecy: La Tournette, Parmelan, Arcalod. ...
In 1945, he made his first races with Lionel Terray: the north face of Les Droites and the east face of Le Moine. He followed, among other things, and always in the company of Lionel Terray, the fourth ascent of the Walker spur in 1946, the second ascent of the Eigerwand wall in 19472. In 1948, he became a member of the Compagnie des Guides de Chamonix . In 1949, he chained the ascents. In particular, he undertakes to climb three reputedly difficult routes in a single day (east ridge of the Crocodile, east face of the Caiman, Ryan route in Plan).
After his return to Orly airport, a stay at the Vaugirard clinic and the presentation of the Legion of Honor, Louis Lachenal returned to Chamonix. He then gave a series of lectures (Knowledge of the world), starting in 1951. He began to drive cars before resuming training and climbing. He took over the management of the French alpine skiing and slalom team and climbed Mount Rose in August 1955.