The Amazon River is the largest river in the world by volume accounting for a fifth of the worlds total river flow spanning from Peruvian mountain streams into the atlantic ocean via the entire length of Brazil .
The Tay River is the longest river in Scotland spanning from the Highlands down through Perth eventually reahing hte sea through the Firth of Tay, south of Dundee. It is the largest river in the United Kingdom by volume of water discharge with a catchment of 2000 square miles. The river is rich in salmon and other wildlife with access across the river via the Tay Rail Bridge famous for the Tay Bridge disaster.