OK, then tell us what they are. Or did you already with Navarra, Aragón, etc.? Those aren’t exactly obscure.
The Badlands of New Mexico.
The word can refer to any desert region, but it often refers to lava fields surrounding ancient volcanoes.
It is a translation of the Spanish term “malpais”.
“Mal” = “bad”
Pais" = “land” or “country”
“Pais” is singular. The plural would be “paices”. But a lot of Anglos see the “s” on the end and assume it must be plural. So “malpais” gets translated as “badlands” rather than “badland”. When talking about a specific place, people will describe it as “a malpai” or “the malpai”.
WA should have known better than to pick it…