The river then flows southward through a steep gorge known as the Kali Gandaki Gorge, or Andha Galchi, between the mountains Dhaulagiri, elevation 8,167 metres (26,795 ft) to the west and Annapurna I, elevation 8,091 metres (26,545 ft) to the east. If one measures the depth of a canyon by the difference between the river height and the heights of the highest peaks on either side, this gorge is the world's deepest. The portion of the river directly between Dhaulagiri and Annapurna I, 7 kilometres (4 mi) downstream from Tukuche), is at an elevation of 2,520 metres (8,270 ft),[3] which is 5,571 metres (18,278 ft) lower than Annapurna I. The river is older than the Himalayas.