At certain points in the course of many rivers, water descends vertically; these waterfalls may come where the river leaves a plateau, where it crosses bands of resistant rock, or where it encounters a fault scarp. On rivers, waterfalls are often wider than they are tall; in mountain streams, they tend to be higher than they are wide. In almost every case the sound and sight of glassy water turning into froth and fury is an irresistible lure to humans. Niagara Falls, the continent’s highest-volume cataract, was one of the ﬁrst headquarters of the sublime for American painters, writers, and other travelers. Waterfalls are in constant motion in more ways than one—they migrate slowly upstream as the lip erodes and the wall is undercut in the plunge pool at the base.
How could they love / these Falls, which have fallen / further, which sit dry / and quiet as a / graveyard now? / These Falls are that place / where ghosts of salmon jump, / where ghosts of women mourn / their children who will/ never ﬁnd their / way back home.
— Sherman Alexie, “The Place Where the Ghosts of Salmon Jump”