Khyber Pass (kĪˈbər) [key], narrow, steep-sided pass, 28 mi (45 km) long, winding through the Safed Koh Mts., on the Pakistan-Afghanistan border; highest point is 3,500 ft (1,067 m). The routes through it link the cities of Peshawar, Pakistan, and Kabul, Afghanistan. For centuries a trade and invasion route from central Asia, the Khyber Pass was one of the principal approaches of the armies of Alexander the Great, Timur, Babur, Mahmud of Ghazna, and Nadir Shah in their invasions of India. The pass was also important in the Afghan Wars fought by the British in the 19th cent. The Khyber Pass is now traversed by an asphalt road and an old caravan route. A railroad (built 1920–25), which passes through 34 tunnels and over 92 bridges and culverts, runs to the Afghan border. Pakistan controls the entire pass.