Band-e Kaisar
The Band-e Kaisar (Persian: بند قیصر, "Caesar's dam"), Pol-e Kaisar ("Caesar's bridge"), Bridge of Valerian or Shadirwan was an ancient arch bridge in the city of Shushtar, Khuzestan province, Iran, and the first in the country to combine it with a dam. Built by the Sassanids during the 3rd century CE, using Roman prisoners of war as the workforce, it is the easternmost example of Roman bridge design 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 500m long overflow dam over the Karun, Iran's most effluent river, was the core structure of the Shushtar Historical Hydraulic System (سازه‌های آبی شوشتر) from which the city derived its agricultural productivity. The arched superstructure carried across the important road between Pasargadae and the Sassanid capital Ctesiphon.