Falak-ol-Aflak Castle (in Persian: دژ شاپورخواست Dež-e Shāpūr-Khwāst, in ancient times known as Dežbār as well as Shāpūr-Khwāst) is a castle situated on the top of a large hill with the same name within the city of Khorramabad, the regional capital of Lorestanprovince, Iran. This gigantic structure was built during the Sassanid era (224–651).
The Khoramabad River runs past the eastern and south-western side of the Falak-ol-Aflak hill providing the fortress some natural protection on those sides. Today, the western and northern sides of the hill are bordered by the residential districts of Khorramabad.
Falak-ol-Aflak castle is amongst the most important structures built during the Sassanid era. It has been known by a number of names since it was built over 1800 years ago. Recorded names have referred to it as Shapur-Khast or Sabr-Khast fortress, Dezbaz, Khoramabad castle, and ultimately the Falak-ol-Aflak Castle.
Reference: https://en.wikipedia.org/wiki/Falak-ol-Aflak_Castle
