A bridge is a structure built over something (such as a body of water, valley, road, rail, or could be just as simple as two book) without blocking the way underneath. It is constructed for the purpose of joining or providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross. Bridge could be as highly engineered and expensive to build as a Bay Bridge in San Francisco and it also could be simple rope joining two ends like a zip line. Here are some bridges to know the concept.

 

 

Bay Bridge San Francisco

 

Kids Crossing Rope Bridge

Normal bridge

 

Diy Bridge by books and paper