A simple suspension bridge (also rope bridge, swing bridge (in New Zealand), suspended bridge, hanging bridge and catenary bridge) is a primitive type of bridge that is supported entirely from anchors at either end and has no towers or piers. However, it may have saddles. In such bridges, the deck of the bridge follows the downward and upward arc of the load-bearing cables, with additional light ropes at a higher level used to form a handrail. Alternatively, stout handrail cables supported on short piers at each end may be the primary load-bearing element, with the deck suspended below. Suspended well from two high locations over a river or canyon, simple suspension bridges follow a shallow downward catenary arc and are not suited for modern roads and railroads. Owing to practical limitation in the grade (i.e. the deck being an arc, not flat) and the response to dynamic loads of the bridge deck, this type is quite restricted in its load-carrying capacity relative to its span. This type of bridge is considered the most efficient and sustainable design in developing countries, however, especially for river crossings that lie in non-floodplain topography such as gorges.