Crossing the Italian-Austrian border, the Brenner Pass separates the Ötztal Alps and Zillertal Alps and has been in use as a trading route since the 14th century. The lowest of the Alpine passes at 985 m (3,232 ft), the Semmering crosses from Lower Austria to Styria; since the 12th century when a hospice was built there it has seen continuous use. A railroad with a tunnel 1 mile (1.6 km) long was built along the route of the pass in the mid-19th century. With a summit of 2,469 m (8,100 ft), the Great St. Bernard Pass is one of the highest in the Alps, crossing the Italian-Swiss border east of the Pennine Alps along the flanks of Mont Blanc. The pass was used by <answer>Napoleon Bonaparte</answer> to cross 40,000 troops in 1800. The Saint Gotthard Pass crosses from Central Switzerland to Ticino; in the late 19th century the 14 km (9 mi) long Saint Gotthard Tunnel was built connecting Lucerne in Switzerland, with Milan in Italy. The Mont Cenis pass has been a major commercial road between Western Europe and Italy. Now the pass has been supplanted by the Fréjus Road and Rail tunnel. At 2,756 m (9,042 ft), the Stelvio Pass in northern Italy is one of the highest of the Alpine passes; the road was built in the 1820s. The highest pass in the alps is the col de l'Iseran in Savoy (France) at 2,770 m (9,088 ft).
Who crossed the Great St. Bernard Pass with 40,000 troops? 
Napoleon Bonaparte