Shushtar Historical Hydraulic System is an island city from the Sassanid era with a large irrigation system from which Shushtar derived its agricultural productivity,and which has been designated World Heritage Site by the UNESCO in 2009. One of structures of the Hydraulic System was Band-e Kaisar (“Caesar’s dam”), a Roman arch bridge, one of the first in the country to combine it with a dam.When the Sassanian Shah Shapur I defeated the Roman emperor Valerian, he is said to have ordered the captive Roman soldiers to build a large bridge and dam stretching over 500 metres.Lying deep in Persian territory, the structure which exhibits typical Roman building techniques became the most eastern Roman bridge and Roman dam. Its dual-purpose design exerted a profound influence on Iranian civil engineering and was instrumental in developing Sassanid water management techniques.The approximately 500 m long overflow dam over the Karun, Iran’s most effluent river. The arched superstructure carried across the important road between Pasargadae and the Sassanid capital Ctesiphon. Many times repaired in the Islamic period, the dam bridge fell out of use in the late 19th century, leading to the degeneration of the complex system of irrigation….. The ancient Shooshtar waterfalls in Iran’s southern Khuzestan Province have been registered on the UNESCO 2009 World Heritage List. “The decision was made at a World Heritage Committee meeting in the city of Seville in Spain,” said Iran’s representative to UNESCO, Mohammad Reza Dehshiri on Friday. The city of Shooshtar is famous for its water supply installations, which date back to the Sassanid era (224-651 CE). The country’s largest river, Karun which encircles the city has created beautiful waterfalls in different parts of Shooshtar. Shooshtar is an ancient fortress city in the Khuzestan province in southwestern Iran. It is approximately 92 km away from Ahvaz, the centre of the province. Iran has so far registered ten historical sites on UNESCO’s World Heritage List including Persepolis, Pasargadae and Bisotun.