How does the Brahmaputra River cross the eastern Himalayas?

The Brahmaputra River crosses the eastern extremity of the Himalayas by flowing through the Yarlung Tsangpo Grand Canyon, which is recognized as one of the world's deepest gorges.1

Before reaching this point, the river—known in its upper course as the Tsangpo—cuts through a series of narrow gorges between the mountainous massifs of Gyala Peri and Namjagbarwa (Namcha Barwa) in Tibet, characterized by numerous rapids and cascades. As it traverses the eastern Himalayas, the river is flanked by canyon walls that rise to heights of 16,500 feet (5,000 meters) or more on each side. Upon exiting these mountains, the river enters the Indian state of Arunachal Pradesh, where it is known as the Dihang (or Siang) River, before descending into the plains of Assam.1