The Grand St Bernard Pass at 2,473 metres is the oldest documented Alpine crossing — used since the Bronze Age and mentioned by Julius Caesar. The road from Martigny climbs 40 km through vineyards, then pine forests, then bare rock to the hospice at the top, still operated by Augustinian monks and still home to the Saint Bernard dogs that gave the breed its name. The views from the pass are spectacular.
The road is open from late May to October; outside those months, the tunnel beneath the pass (toll-road) keeps the route to Italy open year-round. The hospice museum covers the pass's history across three millennia. On the Italian side, the descent to Aosta takes about an hour. If you have time, the Fenêtre d'Arpette walk from near the pass is among the most dramatic ridge walks in the western Alps.