Why have mountain passes been important transportation routes in the Alps?

Mountain passes have been vital to the Alps because the range’s rugged, steep terrain historically acted as a significant barrier to transportation. Since Celtic times, these passes have served as essential communication links, connecting otherwise isolated valleys.1

Their importance as transportation routes stems from several factors:

• Connectivity: Passes evolved from simple paths into major trade and travel corridors, such as the Brenner Pass, which has functioned as a primary route between Germany and Italy since Roman times.12
• Economic Integration: By facilitating movement, these routes enabled trade and the growth of settlements like Chur and Andermatt.1
• Modern Infrastructure: The development of carriage roads, railways, and eventually modern highways and tunnels has allowed for year-round transit, effectively ending the isolation of many Alpine regions.123

While these routes have been crucial for economic development and the growth of 20th-century tourism, the increased traffic facilitated by tunnels has also contributed to the degradation of the fragile Alpine environment.14