Five miles meandering with a mazy motion
Through wood and dale the sacred river ran,
Then reached the caverns measureless to man,
And sank in tumult to a lifeless ocean:
And 'mid this tumult Kubla heard from far
Ancestral voices prophesying war!

These lines from "Kubla Khan" evoke a vivid and mysterious landscape, reflecting the Romantic fascination with nature's beauty and chaos. The "sacred river" winds through an idyllic setting before plunging into the unknown, symbolizing a journey from order into disorder. This imagery mirrors the poem's own structure, shifting from the serene to the tumultuous. The term "measureless to man" suggests the limits of human understanding, while the river's descent into a "lifeless ocean" hints at inevitable destruction or oblivion.

In this context, the "ancestral voices prophesying war" introduce an ominous note, disrupting the preceding tranquility with a forewarning of conflict. The voices serve as a reminder of cyclical violence in history, aligning with Romantic themes of the sublime and the terrifying. This moment underscores the transient nature of peace and beauty, suggesting that even in paradise, echoes of past and future conflicts persist, beyond human comprehension or control.