It's the Great Plains
plateau
what is a large,high,almost level area of land
Plain
plateau
A Plain
a plateau
a plateu
Brazil
The name given to a large area of level land on the Earth's surface is a plateau. A plateau also typically is elevated above the surrounding area. Such areas are also sometimes called tablelands.
A large level area high above ground is commonly known as a plateau. Plateaus are elevated flat regions with steep sides, often formed through geological processes like erosion or volcanic activity. They can be found all over the world and are important habitats for various plants and animals.
That I believe, would be the Earth's Crust.