Though the poem’s verses leave its exact setting undefined, its basis in Wilfred Owen’s real-life experiences suggest that it takes place in France during World War I. The actual march and gas attack that inspired the poem occurred in early 1917. The speaker describes surroundings that are far from idyllic. His unit was marching through “sludge” (2), away from “the haunting flares” (3) of battle. This grim imagery turns eerie when the chlorine gas-shells drop and the muddy environment starts to resemble a “green sea” (14). Though most of the poem’s imagery is centered around the bodies of the characters, these uninviting and ultimately unnerving place details demonstrate the unappealing realities of war. Midway through the poem, the speaker adds another layer to its primary setting of World War I France by revealing that the scene described occurs night after night in “smothering dreams” (17). That...