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 , 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 long was built along the route of the pass in the mid-19th century. With a summit of , 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 Napoleon Bonaparte to cross 40,000 troops in 1800.