Most of us carry a private theory about the place we live, and the poem is about the night one such theory collapses. The speaker "used to think that this city was dead at night," then finds out on a cool summer evening that it "wasn't." The central idea is that a city's life can't be judged from the outside. The speaker only discovers it by stepping into it, and once inside, individual people stop being individuals and become part of one living thing.
The opening is plain and conversational, almost a confession. There is no grand announcement, just a changed mind. The hedge in "it seems it wasn't" is easy to miss, but it makes the speaker sound surprised and not quite sure of the evidence. The verb tense is also slightly off: the speaker uses the past ("wasn't") for a night that is still going on, as though already looking back on the moment of revelation while living through it. Then comes the quiet turn of "Everyone was out / Myself included." The line break does the work. The second line is a small, almost sheepish afterthought, and it admits that the speaker is part of the proof against his own old belief. The poem never says why the city once seemed dead, but the phrasing suggests that the speaker's own absence from the streets may have been part of the reason.
The middle lines shift from statement to image, and the syntax tightens. "Stacked upon each other / Life upon life / Body against body" is built from parallel phrases that pile up as the crowd does. "Stacked" is a surprising verb, the kind you'd use for crates or chairs, and it makes the crowd feel dense and almost mechanical. "Life upon life" corrects that at once by repeating the same noun, so that no one is more than a copy of the next. Then "upon" gives way to "against," and the picture turns from vertical piling to sideways pressure, from objects balanced on one another to people in contact. The "cool" air is a small counterweight. The poem never mentions heat, but the coolness leaves the warmth of crowded bodies for the reader to supply.
The most striking image is "The writhing single organism of my city." The metaphor turns the crowd into one animal, and "writhing" is a deliberately double-edged word, since it can suggest pain or pleasure. That ambiguity keeps the line from sounding like a tourist-board slogan. "Single" erases the separate people we have just been shown, and "my" claims the whole creature for the speaker. Joining the crowd has changed his relationship with the city from observer to belonging.
The ending is where the poem's shape becomes clearest. The first lines run long and talkative, but the last three shrink to single words: "Awake / Alive / Resurgent." Each step goes a little further. Being awake is only consciousness, being alive is biology, and "Resurgent" is something larger, a rising again. The first two words share their opening vowel and nearly echo "Life" from the line before, so they sound like a pulse. "Resurgent" breaks that pattern with its longer, Latinate body, and it picks up the title. It also answers the poem's first word of judgment, "dead," since you can only resurge if you have been down. There is no end punctuation anywhere in the poem, and the final word is an adjective with no noun after it, so the city seems to be still rising when the poem stops.
There is no rhyme, and the poem doesn't need any. The only echoes are "night" returning in line five, "life" folding into "alive," and the shared sound of "awake" and "alive." These are enough to hold such short, unfussy lines together. The poem names no streets, landmarks or dates, which makes the city any city, and readers can easily put their own in its place.
The poem's significance is its modest scale and its lack of irony. It records one small change of mind and treats it as something worth celebrating. The risk of ending on an abstract word like "Resurgent" is that it tells instead of shows, but the earlier bodies and the writhing organism have already earned it. What the poem offers, finally, is an honest account of a pleasure many people know, which is going out into a crowd and finding that the place you thought was asleep has been awake all along.