Tundra is the name for a broad plain that exists in a polar area. Words that are related to tundra are wasteland, expanse, plateau, and flatland.
The answer is a plain.
I believe it is PLAIN
plain
Plain
This is fairly close to the definition of a "coastal plain."
a broad area of flat or gently rolling land is called a plain.
A plain
Serengeti plain
Serengeti Plain
Serengeti Plain
Serengeti Plain
Serengeti Plain