The lovely poem "Composed upon Westminster Bridge, September 3, 1802" by William Wordsworth describes London as it was before the ravages of the Industrial Revolution filled it with pollution and colored the buildings pallid shades of gray. In Wordsworth's vision, the air is clear and smokeless. It seems to be just after sunrise, as the poem speaks of the "beauty of the morning," the "first splendor" of the sun, and the still-sleeping houses in the "bright and glittering" dawn.
Wordsworth is struck by the peace and calmness of the scene, as exemplified by the river gliding along and the ships and buildings set against the open sky. The poet writes that the city wears the morning's beauty like a garment, which means an article of clothing. When in the last line he writes "that mighty heart is lying still," Wordsworth is comparing the city to a living being at rest.
Historically, Wordsworth once wrote that he composed the poem, or at least got the idea for the poem, while riding over the bridge on the roof of a carriage. We can imagine how beautiful the vision of the city in the first light of morning must have been to inspire him so much that he wrote this amazing poem.