“The Rime of the Ancient Mariner” has a nested structure where one narrative sits inside another. Because of this nested structure, the poem features two distinct settings that contrast with each other starkly in terms of mood. Although we don’t have a lot of concrete details about these settings, they may be usefully classified in terms of a basic distinction between land and sea. The poem opens on land. The precise location isn’t clear, but the mood is one of joyful celebration, linked to the occasion of a wedding and its distinctive “merry din” (line 8). As the Mariner begins to tell his tale, however, we are imaginatively whisked away to the ocean, where most of the poem’s narrative takes place. In contrast to the celebratory mood of the wedding, the Mariner’s tale emphasizes what’s dreadful about life at sea, with its isolation, the constantly shifting weather, and a host of other perils. In addition to the contrast of moods, the distinct settings also set up a contrast between the natural and the supernatural. Whereas the wedding celebration is grounded in the naturalness of ordinary life, the sea narrative is full of bizarre supernatural phenomena.