On the banks of the Brahmaputra it is hard to get a sense of where the river starts and ends. It begins far away as a Tibetan mountain stream. On the floodplains of Assam, though, its waters spread as far as the eye can see, merging with the horizon and the sky.
From here it continues through north-eastern India into Bangladesh, where it joins with the Ganges to form a mighty river delta.
For centuries the Brahmaputra has nourished the land, and fed and watered the people on its banks.
Today, though, India and China's growing economies mean the river is increasingly seen as a source of energy. Both countries are planning major dams on long stretches of the river.
In Assam the plans are being greeted with scepticism and some fear.
The fear is that dams upstream could give China great power over their lives. And many in Assam worry whether China has honourable intentions.
After a landslide in China in 2000, the river was blocked for several days, unknown to those downstream.
When the water forced its way past the blockage Assam faced an oncoming torrent. There was no advance warning. There are concerns this could happen more frequently.
Some also believe that China may divert water to its parched north - as it has done with other southern rivers.
India's central government says China has given them assurances about the new Tibetan dams.assam ] [ china ] [ india ]