Bottleneck (K2) Bottleneck (K2) The Bottleneck is a location along the South-East Spur, known also as Abruzzi Spur— the most used route to the summit of K2, the second-highest mountain in the world, in the Karakoram, on the border of Pakistan and China. The Bottleneck is a narrow couloir, which is overhung by seracs from the ice field east of the summit. The couloir is located only 400m below the summit, and climbers have to traverse about 100m exposed to the seracs to pass it. Due to the height (8200m) and the steepness (50-60 degrees) this stretch is the most dangerous part
K2 unable to keep pace. The mountain was first surveyed by a European survey team in 1856. Team member Thomas Montgomerie designated the mountain "K2" for being the second peak of the Karakoram range. The other peaks were originally named K1, K3, K4, and K5, but were eventually renamed Masherbrum, Gasherbrum IV, Gasherbrum II, and Gasherbrum I, respectively. In 1892, Martin Conway led a British expedition that reached "Concordia" on the Baltoro Glacier. The first serious attempt to climb K2 was undertaken in 1902 by Oscar Eckenstein, Aleister Crowley, Jules Jacot-Guillarmod, Heinrich Pfannl, Victor Wessely, and Guy Knowles via the Northeast