The poem is like a series of snapshots of New York City as seen from the waterfront. Each stanza is a different Polaroid (or several Polaroids), showing a new scene but ultimately revolving around the figure of the Brooklyn Bridge. We see office buildings, the subway, Wall Street, the Statue of Liberty, and even have time to catch a movie. Crane should have gotten himself licensed as an official NYC tour guide.
Because the bridge is so distinctive and central to the poem (and because it's awesome!), you should check out some photos if you haven't yet had the chance to walk across it and eat a pizza pie at Grimaldi's in Brooklyn. The bridge is known for its unique cables that fan out from the towers, for its heavy stone feel, and for the medieval-looking arches in the towers. Though it looks old-fashioned now, in Crane's time it was a symbol of modern progress and pragmatic achievements in engineering. New York City is also the home of Wall Street, an you definitely get the impression of being in a hub of commercial and cultural excitement.
One of the most notable things about the setting of the poem is the amount of motion it contains. Birds wheeling in circles, elevators dropping, bedlamites scuttling, traffic skimming, the bridge vaulting… everything is alive and moving. Only the speaker himself seems stationary, as he waits by the piers and looks at the bridge. The world spins around him in a frenzy of activity. Even the day is passing by quickly. The poem begins at dawn, and Crane carefully notes the passage of noon, the afternoon, evening, and night. He also notes the season passing by: it's winter, and the year is quickly coming to an end. It's snowing, or at least there is some snow cover.
At the end of the poem, Crane suddenly extends the bridge beyond New York. It makes a great, metaphorical leap over the American prairies to unite the nation from coast to coast. Now isn't that so typical of New Yorkers – always thinking their city is the center of the universe! But we'll admit it: we do love New York, and the Brooklyn Bridge.