The Aiguille de Bionnassay (elevation ) is a mountain in the Mont Blanc massif of the Alps in France and Italy. It has been described as "one of the most attractive satellite peaks of Mont Blanc", and is located on its western side. The mountain's south and east ridges form the frontier between the two countries, and its summit is a knife-edge crest of snow and ice. Reaching it via any route provides a "splendid and serious snow and ice climb". Glaciers Three significant glaciers originate on the slopes of the mountain: The Glacier de Bionnassay, the Glacier de Bionnassay Italien, and the Glacier de Miage. The Glacier de Bionnassay is the most obvious glacial feature, arising on the north and north-west slopes of the Aiguille de Bionnassay as well as from the western side of the Dôme du Goûter and the Aiguille du Goûter. It descends for approximately 4.5 km, flowing north-westwards before turning north at the foot of the Nid d'Aigle to end some distance above the settlement of Bionnassay, continuing as the Torrent de Bionnassay. This hanging glacier on the north-west face of the Aiguille de Bionnassay provides a route of access for mountaineers with ice-climbing skills. The Glacier de Bionnassay Italien arises from a cirque between the south eastern side of the Aiguille de Bionnassay, the Col de Bionnassay and the Calotte des Aiguilles Grises. It descends south-south west for 2.5 km below the Col Infranchissable, then turns south-east to merge with other glaciers, thence continuing as the Glacier du Miage (Ghiacciaio del Miage) – a total distance of approximately 9 km, forming the longest glacier in Italy. The Glacier de Miage – not to be confused with the much larger Glacier du Miage on the Italian side (see above) – forms from snows collecting between the Aiguille de Tricot and the south-western face of the Aiguille de Bionnassay. The glacier descends in a south-westerly direction for approximately 2.5 km. Alpinism History The first ascent of the Aiguille de Bionnassay was undertaken on 28 July 1865 by Florence Crauford Grove, Edward N. Buxton and Reginald S. McDonald, with guides Jean Pierre Cachat and Michel Payot. They ascended the north-west face to reach the ridge above the Aiguille de Tricot, from where they continued to the knife-edged summit ridge, arriving in a thunderstorm. A detailed account is given below. The mountain's south ridge was first climbed on