A full-size segment identical to those that make up the Penobscot Narrows Bridge shows how the span was built from 181 hollow segments suspended on cables from 442-foot-high pylons. Crews built the segments in all kinds of weather 150 feet above the river and its steep banks. Each segment weighs about 300,000 pounds and contains some 70 cubic yards of concrete and 20,000 pounds of steel. Each is 12 feet 10 inches tall, 31 feet wide at the base, and 57 feet 6 inches wide on top. Four crews constructed the complex span structure, one crew on each side of the two pylons, using movable steel forms and proceeding outward from each pylon in both directions to balance the weight. The segments were ultimately connected to the abutments on the shores and at the bridge's mid-span.