Izad-Khast Castle - Credit: Wikimedia Commons
The Izad Khast Castle is located in Izadkhast in the Fars Province, central Iran. The castle was built during the Sassanid Empire (224 to 651 AD) and functioned as fortified walled city on the ancient Silk Road that ran through central Iran. It is the second largest adobe building in the world after Arg-e Bam. Read more on Wikipedia
Source: en.wikipedia.org