The Scarlet Letter
(9) Mount Everest
Honestly, we were tempted to give this one a 10. No lie: it's a toughie. Check out this sentence:
Doomed by his own choice, therefore, as Mr. Dimmesdale so evidently was, to eat his unsavory morsel always at another's board and endure the lifelong chill which must be his lot who seeks to warm himself only at another's fireplace, it truly seemed that this sagacious, experienced, benevolent old physician, with his concord of paternal and reverential love for the young pastor, was the very man, of all mankind, to be constantly within reach of his voice. (9.16)
"Unsavory," "sagacious," "concord": these words aren't hard in and of themselves, but stack them all together in a 77-word-long sentence full of dependent clauses, and the hike up Mt. Scarlet Letter starts to get pretty steep. And that's not even to mention all the tricky ideas about fate, community, and forgiveness.
But take it from us: there's a reason this book has stayed on required reading lists for decades. (And it's not because your teachers like to torture you.)