the recesses of something
From Longman Dictionary of Contemporary Englishthe recesses of somethingthe recesses of somethingIN/INSIDEthe inner hidden parts of something the deep recesses of the cave fears hidden away in the darker recesses of her mind → recessExamples from the Corpusthe recesses of something• the dark recesses of the basement• He had tried to sleep, but the horrific apparitions surfaced out of the recesses of his unconscious and frightened him.