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"Composed upon Westminster Bridge, September 3, 1802" expresses the reflections of William Wordsworth as he looked out upon the glorious sights of the city of London visible from the bridge. Contrary to the impression given by the title, he probably did not compose the entire poem at one time; he may have begun it as he was leaving London in late July of 1802, finishing it upon his return on September 3.
At any rate, the poem recognized the magnificence and beauty of the still, quiet morning he beheld from his vantage point on the bridge. He observed "Ships, towers, domes, theatres, and temples" as he looked out and understood that it was possible to see them "All bright and glittering in the smokeless air" because it was early in the morning. He compares their grandeur to "valley, rock, or hill" and contends that "Earth has not anything to show more fair" than the sights of London.