The project of building a bridge is a canonical example of what John Law (1987) has termed `heterogeneous engineering', involving the arrangement of human and nonhuman elements into a stable artifact. This paper reports ethnographic research on the work of civil engineers engaged in designing a bridge scheduled for completion by the year 2004. My emphasis is on a view of bridge-building as persuasive performances that both rely upon and reflexively constitute the elements to be aligned. The work of designing a bridge, on this view, is as much a matter of story-telling as of analysis, calculation, and work with concrete and steel.