Western Cordillera- What is it?

The Western Cordillera is one of Canada's seven landform regions (Arctic Lowlands-Hudson Bay Lowlands, Appalachians, Canadian Shield, Great Lakes-St. Lawrence Lowlands, Innuitian Mountains, Interior Plains, Western Cordillera). Underneath is a picture of all the landform regions of Canada
Green-Canadian Shield
Pale Yellow-Interior Plains
Blue-Western Cordillera
Pink-Appalachians
Yellow-Arctic Lowlands-Hudson Bay Lowlands
Orange-Great Lakes-St. Lawrence Lowlands
Puplre-Innuitian Mountains