How does Kim Addonizio use imagery in Knowledge?

Much of the imagery is created by the reader within the context of the poem. The poem focuses on the most horrific things that take place in the world, although it does not mention any horrors in particular. Addonizio begins the poem with a lengthy dependent clause that allows the reader to slowly come to an understanding of the assertion that even though one might think one knows the depth of human cruelty and the extremes of barbarity, some events can still prove utterly appalling.