A pontoon bridge is a type of floating bridge that uses pontoons or barges to support the bridge deck. These structures are often used in situations where traditional bridges are impractical, such as over rivers or lakes. They can be quickly assembled and disassembled, making them useful for military operations or temporary crossings. Pontoon bridges are typically made from materials like steel or reinforced concrete and can accommodate vehicles and pedestrians. They are designed to withstand water currents and waves, ensuring stability. Historical examples include the use of pontoon bridges during the American Civil War and in various military operations.