Here is the sentence of my question.
希望に満ち溢れていたはずの"あなた"がなぜあんなに荒凉とした場所にうずくまっていたの。
I can understand what it's trying to say to some degree yet it confuses me why とした is used in the sentence.
With the wonder I checked とした up in the dictionary and got no explanatory answer. And I wonder if it's an adjective or a particle added to modify nouns and turn them into adjectives.