Towers are the most visible structural elements of long-span bridges. They project above the superstructure and are seen from all directions by viewers and by users. Towers give bridges their character and a unifying theme. They project a mnemonic image that people remember as a lasting impression of the bridge itself. As examples of the powerful imagery of towers, contrast the elegant art deco towers of the Golden Gate Bridge (Figure 3.1) with the utilitarian but timeless architecture of the towers of the San Francisco-Oakland Bay Bridge (Figure 3.2). Or contrast the massive, rugged stone towers of the Brooklyn Bridge (Figure 3.3) with the awkward confusing steel towers of the Williamsburg Bridge in New York City (Figure 3.4).