Hidden deep behind the mountains south and east of the sichuan-Tibet Hwy,the swollen Yarlung Tsangpo makes some dramatic U-turns and crashes over a series of spectacular fall.through what chinese scientists claim is the world's deepest gorge, with 7756 Namche Barwa and 7151m Gyala Pelri towering over either side of the gorge.only 27km apart.the gorge records a depth of 5382m (almost three times the depth of the Grand Canyon) with a length of 496km,at one point the river narrows to a mere 20m.before bursting out into the Asssmese plain as the vast brahmaputra river.</p>