is there a grand tunnel

Yes, there is a grand tunnel known as the Gotthard Base Tunnel in Switzerland. It is the world's longest railway tunnel and the deepest traffic tunnel, stretching 57.09 km (35.47 miles) through the Alps. It connects the Swiss cantons of Uri and Ticino, providing a flat, low-level route beneath the mountain range. Opened in 2016, the tunnel is a major engineering marvel and key transport link between northern and southern Europe, designed primarily to increase freight capacity and reduce travel time across the Alps.