1) Booming in the extreme 2) Furthest underwater 3) Hardest to fathom 4) Least obvious 5) Least shallow 6) Like some apologies 7) Like some sympathies 8) Lowest of 500 tepees 9) Mariana Trench superlative 10) Most inscrutable 11) Most mysterious 12) Most obscure 13) Most philosophical 14) Most profound 1) Inmost 2) Innermost