with as balanced cantilever, the span is balanced by cantilevers going in the opposite direction. If these are anchored into solid foundations, they are called anchor arms. In a bridge built on two foundation piers, there are four cantilever arms: two which span the obstacle, and two anchor arms which extend away from the obstacle. Because of the need for more strength at the balanced cantilever's supports, the bridge superstructure often takes the form of towers above the foundation piers. The Commodore Barry Bridge is an example of this type of cantilever bridge.