The Jungfraubahn (JB), which is also rack-and-pinion throughout, starts at Kleine Scheidegg and runs 9 kilometres through tunnels in the Eiger and Mönch, leading to the Jungfraujoch, a saddle between the Mönch and the Jungfrau summits. At the saddle are a visitor centre and an observatory. The Aletsch Glacier, largest in Europe, runs to the south toward the Rhône valley.