Jungfrau, well-known Swiss peak (13,642 feet [4,158 metres]) dominating the Lauterbrunnen valley and lying 11 miles (18 km) south-southeast of the resort of Interlaken. The scenic mountain separates the cantons of Bern and Valais and is in the Bernese Alps, two other peaks of which (the Finsteraarhorn [14,022 feet] and the Aletschhorn [13,763 feet]) surpass it in height. The first ascent was made in 1811 on the eastern or Valais side by two Swiss brothers, Rudolf and Hieronymus Meyer. It was not until 1865 that two Englishmen made the first ascent from the difficult western, or Interlaken, side, and in 1927 two guides climbed the south side. One of Europe’s highest railways (constructed 1896–1912) cuts a 4.4-mile-long tunnel through the Eiger and Mönch peaks to the Jungfraujoch, a pass (11,335 feet) between the Mönch and Jungfrau peaks.