Definition, Location, Example
The Corn Belt,is an area in the midwestern United States, roughly covering western Indiana, Illinois, Iowa, Missouri, eastern Nebraska, and eastern Kansas, in which corn and soybeans are the dominant crops ("Corn Belt Region").
I think it could be mountains.. if I'm wrong then I'm sorry..
In the western front, they used Trench Warfare Method
In Trench Warfare the opposing teams would build some sort of trench surrounding their defended area to prevent the the opposing team in invading their protected Area. It's best used as a Defensive method which require the armies to stay hold and defended their position. That's why they're not moving so much