Mountain in the Karakoram Range. The world's second highest peak, it reaches 28,251 ft (8,611 m); it lies partly in China and partly in the Pakistani-administered portion of the Kashmir region. It was discovered and measured in 1856 by Col. T.G. Montgomerie and was given the symbol K2 because it was the second peak measured in the Karakoram Range. In 1954 the Italians Achille Compagnoni and Lino Lacedelli became the first climbers to reach its summit.