Bridges and dams are architectural structures which have been built in the path of caravan roads, ways and on the rivers to both facilitate passage and provide the possibility of storing water for agricultural purposes and other required affairs.
There is not any exact information about the history of building bridges in Iran but the most ancient signs are related to the remnants of a bridge in historical complex of Pasargad. There are remnants of bridges and dams from Sasanian Empire especially in Lorestan, Khuzestan and Fars provinces.
Building bridges in Islamic period was still common, they were built of stones and bricks. For example, it can be pointed out to the remnants of bridges in Daylamites era (Buyid Dynasty) in regions like Rey, Isfahan and Fars such as Amir Dyke in Fars province (Band-e-Azodi) in Safavid dynasty. By the development of road construction, building other architectural constructions such as inns and bridges was flourished. The most prominent bridges of this era are in Isfahan.
Building bridge in Safavid dynasty increasingly focuses on architectural blaze and facade decoration and the distance between piers and width of bridge spans increases.
Two of the most prominent examples of these bridges are Allahverdi Khan Bridge (Si-o-se-pol) and Khaju Bridge in Isfahan having tiling and brickwork which are among the tourism attractions of this province.
There are some other bridges remained from eras after Safavid Dynasty. In Qajar Dynasty and during the premiership of Amir Kabir, many of the bridges were repaired and in Pahlavi Dynasty building bridges was also developed due to paying attention to constructing ways and by the establishment of ways and streets ministry in 1929. In this period, cement and steel structures were used to build bridges and the most salient one is Veresk Bridge on the way of Tehran-Shomal railway.