On the Sublime and Beautiful/Part II/Chapter 13

ANOTHER source of greatness is Difficulty. When any work seems to have required immense force and labor to effect it, the idea is grand. Stonehenge, neither for disposition nor ornament, has anything admirable; but those huge rude masses of stone, set on end, and piled each on other, turn the mind on the immense force necessary for such a work. Nay, the rudeness of the work increases this cause of grandeur, as it excludes the idea of art and contrivance; for dexterity produces another sort of effect, which is different enough from this.