In ancient times, rivers or large water bodies were natural divisions or borders between tow distant lands. Later, people probably found that a fallen log across a stream provided them with a useful footbridge. In jungle areas, they could make a simple foot bridge out of ropes of vines twisted together. When people began to fine then the log and vine bridges could not carry carts and wagons, or large number of people across wider spans, they began to improve their bridges to meet their needs.
Beam Bridges 
Arch Bridges
The most primitive form is the beam or girder bridge consisting of a rigid beam resting at either end on piers. The span may be increased by the use of beams.
This eventually led to creation of truss bridges. These were mainly wooden or metal framework designed for greater strength.
As per written records, the first bridge of wooden beams resting on stone piers was built in 2230 B.C. across the river Euphrates in Babylon Anio River in Italy
Gradually a lot of improvements were made in the art and science of building bridges. In 1779, the first metal bridge was built over Severn River in England Germany Florence , Italy
Today due to the advancement in technology, engineers and architects are able to construct very long and strong bridges. Usually bridges are divided into four categories: 1. Girder or Beam Bridges
Did you know that the longest bridge in the world is humbler estuary bridge of England Sydney harbor bridge of Australia
