There are Himalayas on a detailed map - scheme. Thick lines represent the ridges.
Enlarge >>
The map shows that many rivers flow through the mountains from north to south. How can it be? That is the Himalaya's specificity. The Himalaya are among the youngest mountain ranges on the planet. Rivers flowed in this area when the mountains have not been here yet. Then as a result of tectonic processes gradually began to rise mountains. This is not happening quickly, and  the rivers had time to wash their way through this obstacle. As a result, the river valleys become a huge gorge.
See riverbed in the Himalayas >>