The sandbar is the shifting, mutable barrier at the mouth of a river or entrance to a harbor. In poetry, it symbolizes transition, the liminal zone between fresh and salt water, and the temporary nature of all boundaries. Sandbars are constantly moving, making them unreliable and dangerous, yet they also offer a place where land begins to emerge from the depths. Poets evoke the sandbar in meditations on the threshold of life and death—Tennyson's "Crossing the Bar" being the supreme example—where the voyage ends and the pilot meets the divine. Its sandy nature suggests impermanence and the gentle, rather than violent, dissolution of form.

A sandbar is a long, narrow ridge of sand formed by currents, often submerged and always shifting. In poetry, it symbolizes transition, the liminal zone between fresh and salt water, and the temporary nature of all boundaries. Sandbars are unreliable and dangerous, yet they also offer a place where land begins to emerge from the depths. Alfred Lord Tennyson's "Crossing the Bar" is the supreme example, where the sandbar becomes a metaphor for the threshold between life and death, and the voyage ends as the pilot meets the divine. Its sandy nature suggests gentle, rather than violent, dissolution and change.