original_query: What were Walter Bonatti's notable climbing achievements?
query: What were Walter Bonatti's notable climbing achievements?
answer: Walter Bonatti's notable achievements include a solo climb of a new route on the south-west pillar of the Aiguille du Dru, the first ascent of Gasherbrum IV, and the first solo winter climb of the Matterhorn's north face.  He also made numerous other first ascents and significant climbs in the Alps, Himalayas, and Patagonia.