Normally flowing water, such as rivers will slowly cut through land to form valleys cliffs and trenches.
what do people build to cross deep rivers or valleys?
The Marianas Trench, and many other deep undersea valleys, can be found on the ocean floor.
continental slope
There are more than one term for a deep narrow valley. Glens, canyons, ravines, fjords are terms you could use.
Rift Valleys
colordo
mountains and water falls plateau deep river valleys vaconos
Because many years ago large glaciers passed over the plains, eroding the ground on which they tarvelled on, creating deep valleys.
The term used for narrow deep valleys is "ravine."
The Tibetan Plateau is known for its high elevation, with an average height of over 4,500 meters, making it the highest plateau in the world. It is characterized by vast grasslands, rugged mountains, deep valleys, and numerous rivers and lakes. The plateau is also home to the Himalayas, including Mount Everest, the highest peak in the world.
Those deep valleys are mainly in Wales, in the southwest of Britain.
rift valleys
a glen
what do people build to cross deep rivers or valleys?
rift valleys
Water flows in deep gullies to the upland plateau.
40 meters