In the Elamite times Shushtar was known as Adamdun. In the Achaemenian times its name was Šurkutir. The modern name, Shushtar, is connected with the name of another ancient city, Susa, and means "greater than Shush." During the Sassanian era, it was an island city on the Karun river and selected to become the summer capital. The river was channelled to form a moat around the city, while bridges and main gates into Shushtar were built to the east, west, and south. Several rivers nearby are conducive to the extension of agriculture; the cultivation of sugar cane, the main crop, dates back to 226. A system of subterranean channels called Ghanats, which connected the river to the private reservoirs of houses and buildings, supplied water for domestic use and irrigation, as well as to store and supply water during times of war when the main gates were closed. Traces of these ghanats can still be found in the crypts of some houses. Ibn Battuta visited, noting "On both banks of the river, there are orchards and water-wheels, the river itself is deep and over it, leading to the travelers' gate, there is a bridge upon boats." The ancient fortress walls were destroyed at the end of the Safavid era.
Band-e Kaisar
The Band-e Kaisar is believed by some to be a Roman built arch bridge , and 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, was the core structure of the Shushtar Historical Hydraulic System, a large irrigation complex from which Shushtar derived its agricultural productivity, and which has been designated World Heritage Site by the UNESCO in 2009. 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 Shushtari dialect is spoken in Shushtar and is a dialect of Persian.
Climate
Shushtar has a hot semi-arid climate with extremely hot summers and mild winters. Rainfall is higher than most of southern Iran, but is almost exclusively confined to the period from November to April, though on occasions it can exceed per month or per year.
