Before him is a broad plain stretching out to the horizon.
He called the horses to him and started up to the broad flat plains above.
They stood in the middle of a broad, flat plain.
He stood, staring down at the broad plain below, not really seeing it.
A broad flat plain would be much more to his liking.
Suppose there is a large mountain next to a broad plain.
It has broad central plains with several ranges of low hills.
He passed the time by telling me about the people who lived on that broad plain.
He paused at the plateau and looked out over the broad plains.
She looked away from me, out across the broad plains.