<onlyinclude> The world's longest suspension bridges are listed according to the length of their main span (i.e. the length of suspended roadway between the bridge's towers).</onlyinclude> The length of main span is the most common method of comparing the sizes of suspension bridges, often correlating with the height of the towers and the engineering complexity involved in designing and constructing the bridge. If one bridge has a longer span than another it does not necessarily mean that the bridge is longer from shore to shore (or from abutment to abutment).