The powerful canyon system of the Yarlung-Tsangpo, the upper course of the Brahmaputra, is far more powerful than the Grand Canyon. For 50 millions of years, the concentrated water and sediment masses penetrated with an enormous amount of energy deeper and deeper into the fast rising youngest rocks of our planet. Whereas the icy waters of the Yarlung-Tsangpo rumble down in India, humid warm air masses stream through a chimney up to the mountains and bring with them the subtropical forests of Arunachal-Pradesh to the very heart of the Himalayas. They make the mighty glaciers in the eastern Himalayas expand, whereas most of the Tibetan glaciers are melting.