a tectonic unit whose rocks come from the Apulian plate, a small continent which broke away from Africa (Gondwana) before the Alpine orogeny. The Austroalpine nappes are common throughout all of the Eastern Alps. Climbing history The first ascent was made via the east ridge in 1850 by the 28-year-old topographer Johann Wilhelm Coaz (1822–1918, from S-Chanf) and his assistants, the brothers Jon and Lorenz Ragut Tscharner. On 13 September 1850, shortly after 6 a.m., they left the Bernina Inn (at ) with their measuring instruments. They traversed the Labyrinth (on the Morteratsch Glacier) and headed to the Fuorcla Crast'Agüzza, a col between the Crast' Agüzza and Piz Bernina. They reached the summit at around 6 p.m. Johan Coaz wrote in his diary: "At 6 p.m. we stood on the ardently desired lofty peak. On soil that no human had trodden upon before. On the highest point of the canton at 4052 meters above sea level." "Serious thoughts took hold of us. Greedy eyes surveyed the land up to the distant horizon, and thousands and thousands of mountain peaks surrounded us, rising as rocks from the glittering sea of ice. We stared amazed and awe-struck across this magnificent mountain world." In 1866, the south ridge running from La Spedla was climbed by Francis Fox Tuckett and F. A. Y. Brown with guides Christian Almer and F. Andermatten. They started at midnight from the Alpe Foppa on the Italian side, and reached the summit at 11 a.m., descending to Pontresina only a few hours later. The first attempt to climb the northern ridge, the Biancograt, was made on 12 August 1876 by Henri Cordier and Thomas Middlemore with guides Johann Jaun and Kaspar Maurer. They successfully reached the top of the ridge, Piz Alv, but when they saw the chasm lying between them and the summit of Piz Bernina, they considered it to be beyond their powers and returned down the Biancograt. Cordier later declared the gap to be "absolutely impossible". Exactly two years later, Paul Güssfeldt, accompanied by the guides H. Grass and J. Gross, reached the summit via the Biancograt and accomplished the first complete ascent on this route. The first winter ascent was made on 15 March 1929 by C. Colmus with guides C. and U. Grass. To win a bet worth 200 CHF, Hermann Buhl reached the summit of Piz Bernina from the Boval hut in 6