NARRATOR: Three thirteen-year-olds from the UK are on their way to explore the geography of India ... does the river end? MAP SELLER: Huh? DUA: Where does the river end? The Ganges.

The Ganges river in India is more than 2,500km long and has the most populated river basin in the world. Hundreds of millions of people and a huge range of wildlife rely on the river Ganges. But ...