Bridges
A bridge is a structure designed to span an obstacle, such as a river or valley, allowing vehicles, pedestrians, and other loads to pass across. Most bridges consist of a flat deck, supported by structures such as beams, arches, or cables. These structures rest on a foundation that is carefully designed to prevent the bridge from settling into the subsoil.
Bridges can be constructed in a wide variety of forms, determined by their purpose and location. Simple bridge structures include beam bridges made from logs, and suspension bridges made of ropes or vines.